If you looked around harder, you would have noticed that Sirbomber and Freeza may be harder to reckon with... But they're not impossible
Apart from new ideas, OP3 needs balance. adding the dynamic researching thingy you talked about can cause advantages or disadvantages to form in certain situations, if left random, or would need quite some balancing work to make things balance out. I can't say that if someone gets weapons that fire further, while his opponent gets faster units with added damage, things won't balance out somehow.
OP2 is pretty realistic. There may be some things, but I'm not really sure.
For example: Meteor Defenses... they seem very unrealistic... but they're possible in a thin atmosphere planet. A thin atmosphere makes laser and plasma beams to stay focused well enough over a longer distance.
Weapons:
Lasers-plausible, for above reason.
Microwaves: not sure
Rail Gun - plausible (particle acceleration is not something unheard of)
RPG - more than plausible
Stickyfoam - plausible
EMP - very plausible
ESG - plausible
Acid Cloud - plausible... although it is an interesting and peculiar weapon, clouds of acid like that can be made.
Starflare and Supernova - highly plausible
Thor's Hammer - possible. The way they describe it makes it plausible, but there still are some things that can make things hard for this weapon.
So overall... even the weapons have some scientific basis behind them. Except Microwaves... I failed to see how they work... yet
Buildings spawning units: bad idea. Some of the same reasons as Sibomber said. Building are buildings, units are units. Buildings are built via a construction kit, and that kit can't be used to build a working unit all that easily.
I forgot what else there was to comment.