I think if you're a fan of D&D4 you're going to be super-disappointed.
Ultimately, Star Trek does not in any way reflect a universe concerned with tactical play. So that kind of robust system, where each player has several different and unique options, each with mechanical hooks, is difficult for me to imagine. Though if someone could crack it, I'd be first in line.
To give you an example, the line developer for the CODA Trek game was arguing with one of the company's owners about how much damage a phaser should do in this new system. I was working on the Lord of the Rings Adventure Game at the time and when I walked by to grab a print out, they roped me into their argument. Should it do this X damage or Y damage?
"Ah...it shouldn't do either of those," I said. "If you hit someone with a phaser, they die. They don't just die, they often EVAPORATE. Your only hope is a Dodge test."
"That's not going to make for very satisfying combat encounters."
"Nope! It's Star Trek! If someone pulls a phaser on you, your response should be 'OMG I'M GOING TO DIE' and you should immediately begin wondering how everything went critically wrong and how to avoid this situation in future, should you live."
That's the reality on the ground in the setting. Star Trek characters rarely get in fights and when they do it's just as likely to be with fists and swords because the writer took away their phasers for exactly that reason.
So you're stuck with Skills, really, which I think someone who really liked D&D4 would find unsatisfying. You know, in D&D4, if you use Athletics to jump across a chasm, you roll the die and do some math and that unambiguously determines how far you jump. No GM interpretation necessary.
In all the Trek RPGs, the ENTIRE GAME is GM interpretation. The GM picks a target number based on no objective mechanism, the player rolls.
But since Trek is a highly *narrative* setting, failing a skill check can be a problem. "Well, you didn't ask the right question of the Guardian of Forever, so even though we've only been playing for 15 minutes, we're done."
Which leads to, across every Trek game I've played in, a tendency toward "The GM asks you to make a Skill check, and you roll dice until he is satisfied."
So what I'd do is wait for a post-D&D4 Mass Effect RPG.