I'll need to break this into multiple parts, since these forums, like twitter, don't like big messages. And while it must be under 10k characters, it doesn't say how many i'm using.
I've been using IC2 for years. Since 1.2.5 in fact. However in recent years the mod has become bloated with convoluted and frankly retarded features that go nowhere, poor mod compatibility and machines with no use, but still manage to get later support added to them.
So what am I suggesting? That IC2 be cleaned of all its convoluted mess. And while i'm sure some of the things that need to be cleaned/removed make sense to a small minority, they're unintuitive to the rest of the minecraft world. Already IC2 has declined from being the best tech mod with the most active community to a mod that's actively avoided being put in modpacks, with the least active community.
Now, i'm not saying to tear apart IC2 machines and replace them with a 2-slot interface, with one for fuel and one for output that do everything and cost nothing. Because that would be just as stupid, if not worse. There are enough terrible mods like that that somehow end up popular and spawn dozens of add-ons (*cough*MFR*cough*).
I'm also not going to say that requiring wrenches, power loss and exploding machines are stupid, because I think the people who say that are stupid. Wrenches, power loss and incorrect energy management is a defining aspect of IC2, if not what it's best known for. ("Fairness")
First, i'll start here, outside the mod.
Bug Reporting
It seems to me, to be a completely insane way to report bugs in IC2. I've found one or two bugs and have simply not bothered to report them because of your Mantis bugtracker. No other mod developers use it, and that's not a good thing. Being "special" isn't always a good thing. Especially if involves special caregivers. If it didn't require a new account for it, that might be fine. But as it stands, i'm surely not alone in not wanting to make yet another account for an obsolete bugtracker.
Suggestion: Change to github like every other major developer out there, and never again will bugs fail to be reported. It'll also be easier to sort through and navigate. It doesn't matter if you (the devs) don't like github for some personal preferences, it's about getting bugs reported and github is what all the cool kids use, and because of that no one else needs to make a new account for it.
Changelogs
Seriously, wtf? The last 10+ updates to IC2 have no changelog. The changelog page on curse simply says "bugfixes", not what's been fixed or what, if anything has been added or changed.
Suggestion: Please try to release a concise and short changelog with each update. People always read these to see what's new and what's been fixed. A lack of changelog says "lazy dev".
Now, into the contents of the mod.
Electrolyzer
Why does this even still exist? IC2 has zero inter-mod compatibility in the fluids department, so the oxygen and hydrogen output has no use to other mods, and i've yet to encounter any such use for these two fluids within IC2. So I ask again: Why does this machine even still exist? It's just dead weight and added load time. Once upon a time it made electrolyzed water cells for... I believe it was MFFS forcefields, but that was around 1.4, when IC2 was better... and everywhere.
Suggestion: Remove it until it either has a use, or add something to use the outputs. A gas turbine, fusion reactor, something. Though at this point, a nuclear reactor will likely always take priority over fusion unless there's something bigger and better to use the power, or nuclear reactors get nerfed.
Steam Boiler
I've played with IC2eX for a long time, and never in all my time playing other mods have I ever seen such a terrible boiler design. This boiler is so disasterously convoluted that i've avoided since my first attempt to use it a long time ago, and every few months against my better judgment i've tried to make this thing work time and time again and failed. In fact, on the server I played on once an event was made for players to set up an IC2 steam boiler within an hour. Not a single person even succeded. Half of them gave up, many died from steam explosions (instant disqualification).
IC2eX's steam system is just that bad. Not only is it virtually undocumented, no one has ever done a tutorial, let's play or really anything regarding it. It's firmly avoided by 99% (Rough estimate) of all minecraft players. Hell, Even GregoriousT hasn't touched it, and he's the king of convoluted tech.
Suggestion: Goes without saying: Simplify it. Remove those stupid pressure buttons whose sole purpose is to drip out water and cause explosions, and the static graph that depicts nothing even remotely useful; Follow in the steps of Railcraft. A heat gauge, an internal tank and upgrade slots. If you want to keep your convoluted pressure system in some state, simplify it into a single adjustable valve. A blowoff valve or something. I don't care, as long as it doesn't require a 60 page manual and 3 years of engineering training at a high-paid university in Germany.
Steam Turbine
On the surface, the turbine seems simple enough. Stick in a turbine blade, supply steam, get power. Right? Wrong.
There's an outflow for water, or magical "cold steam" if you're using superheated steam that needs to be taken into account. Unfortunately, if you've never used the turbine before, there's no notification that it outputs anything other than power. So by the time that you get the notification (by supplying steam), you're dead by a steam explosion. *slow clap* It doesn't even use any of the steam, so if you respawn anywhere in the vicinity of the steam turbine, you'll die over and over as steam explosions ensue infinitely.
Because of all the problems brought about by the steam turbine, I suspect this is why the Nuclear Fluid Reactor is virtually unused (surely you've noticed the complete absence of reactor schematics for fluid reactors?).
Suggestion: So what's the steam turbine need? A better GUI, like most IC2 machines. You have a big window with a whole lotta nothing in it. It's a big waste of space. Give the turbine internal tanks of 4 buckets input and 4 for output that's clearly labeled with "steam/superheated steam" when mousing over the input tank and "water/steam" for the output tank. No abrupt explosions from non-existant documentation anymore.
Hell, give it an animated turbine inside the GUI too, that turns when it's functioning to show that it's working and because it "looks cool". Looking cool gets mods far these days. Just look at Immersive Engineering. It's one of the single-worst balanced mods in modern modded minecraft with the compatibility of a home-schooled spoiled millenial redneck. But because it looks cool and is easy to use it makes its way into every modpack now.
Tanks
At first glance, you'd think that a tank would be fairly straightforward. Once again, nope. Not only can you not put anything directly into a tank, you can't even supply anything to a tank from anything within IC2 without multiple pre-configured fluid pulling and ejector upgrades.
As far as storage capacity goes, the IC2 tank is unupgradeable, but stores more than average (used be 8 buckets via BC, now 16 via TE. Behold, the powercreep in action!) at 24b. Once again, the lack of an actual Tank GUI sets the IC2 tank far below its competition. It has what can be described as an item slot, without it saying or showing what its max capacity is.
Suggestion: Another GUI overhaul. Add an item slot for the insertion and removal of cells, buckets, cans, whatever. Along with an actual internal tank graph that rises like any other GUI'd tank with a clearly visible max.