This thread proves that no matter how reasonable and well-written your OP is, you just can't get a mature discussion about mod balance going on these forums.
Power converters: I always felt that any kind of power conversion (including things like Forestry electrical engine or RP blutric engine) were somewhat gamebreaking. Maybe 90% of people using any form of power conversion use it to completely skip the entirety of one mod's power generation. I don't know how mod devs feel about this, but if I was one, I'd be pretty sad about people choosing to avoid 50% of my mod. And I haven't really seen anybody whose actual reason (as opposed to the reason they will talk about) to use power converters is anything else than "I want to power my entire base with IC2 solars and I am too lazy to build anything else". As far as "realism" goes (probably the most voiced reason, however I find it hard to believe there are people for whom this is actually a primary concern), screw that. You can punch a hole in a tree with your fist and the tree stays afloat. What's so incomprehensible about several incompatible types of energy?