I would love to see a machine usage wear/eventual breakdown mechanic introduced to IC2 or included in an optional add-on or config setting. as they are now, once constructed, machines will last forever without wearing out or breaking down. This limits the economic market for buying/selling machines, since once a player has acquired a machine once, they never need to buy one again and have no reason to sell their old one.
My initial concept would be to introduce a 'health bar' to machines much like the health bar on tools. However, instead of having a fixed number of uses after which they are guaranteed to break as tools do, I would have machines carry a per-operation-completed chance of breakdown, the odds of which start at 0% at full health and slowly get worse as the machine accumulates usage wear. The effect of a breakdown would be the same as a failed wrench use. I would add the health bar of the machine to the right-click gui, as well as the inventory slot decal as with breakable tools. I would also add a number-of-completed-operations counter to the right click gui.
The developers can decide whether to have fixed or configurable settings for machine wear. My definitions are my suggestions, and can certainly be tweaked if it makes sense to do so. variables to define would be:
Total Uses (number of uses to go from 100% health to 0% health, I'd say 1562 as default [about 24.4 stacks])
Linear or Tired breakdown chance (linear is 0% chance from 100%-90% health, increasing linearly from 1% chance of breakdown per operation at 89% health to 20% chance of breakdown per operation at 0% health.)
Tiered would use config-defined tiers to determine chance of breakage. for example, 100%-90% health, 0% breakage chance. 89%-60%, 5% chance, 59%-30%, 10% chance, 29-10%, 15% chance, 9%-0%, 20% chance. If tiered setup is undefined, config would default to linear.
I feel that inclusion of this breakdown mechanic would add value and depth to gameplay and facilitate improved SMP player interaction and marketability of IC2 machines, HAYO!