To be fair, almost every franchise misses out on opportunities.
Whether it's lazy developers, not enough time and resources or just them flat out not being capable of doing it.
While I wish there were some elements in Mass Effect, I'm not going to say "good job BioWare! You completely ruined it!"
Everyone seems to prefer ME2 over ME1, I really hope people saying they missed out on opportunities don't feel the same. ME 1 was more accurate to the ME universe. For example, the extremely long cool down on powers, specifically biotics. In the books it's stated that biotics take out so much energy from the person that they can do maybe 4 biotic moves before they're mentally and physically exhausted. Meanwhile in 2 and 3, you can spam powers faster than you can spam hadokens in Street Fighter.
It's not easy for developers. While I'm not going to give them a free pass, they're put in difficult situations a lot.