There are many other series out there with similar themes, on (or off) the Syfy channel, so the limits put upon this team really doesn't make sense. The writers should think outside the box and larger than life. The series needs to be different enough to justify, yet another series about people who are different.
ONE ASPECT I really do see different and enjoy is how Troy's Son (the guy in charge of H.Q.) is sad that he doesn't have a power. I can relate to that fact, as I suspect many people can. Of course, his gaining a power would be great.
And mentioning "a power," people should be able to have more than one power. Some MMORPG games, like FFXI, having a sub-job that you can switch and that boosts your main ability. Giving this to the team members would be GREAT. It would be different. THOUGHT on how they could do this and not jump the shark: First it could just happen, BUT considering some have had their abilities for years - if not decades - time doesn't seem a valid factor. Instead I'd suggest they run into someone who gives them this ability as a reward, which leads into my next thought . . .
As I said earlier, the series needs to be different enough to justify watching it over the other similar series that exist (current or in rerun/DVD). My thought is to over time expand the team to include more than Earth. Yeah, for some this might be jumping the shark, but it could go to explaining why the powers are showing up. The powers do develop naturally but a group of "aliens" are advancing them quicker than evolution and testing to see who can both handle power, as well as do the right thing. Also can they handle more and more power.
This takes us back to the thought on sub-job / multiple powers. The person who adds this to the team could be an human previously tested and selected to help. He's back to recruit people who show HONOR and the ability to do the right thing (in the end). At first they simply discover his ability is to (A) clone the ability of others and (B) augment the powers of other people. While he can't teach them to clone other power, he can teach them how to augment their powers based upon their fellow team members. It could be in real time or like in FFXI, back at a home base. In the field IMHO would be best.
In this team's case, not only can they pass the tests, but Troy's Son is able to gain his own powers, and maybe so does Troy. Yes, they still do stuff on Earth, but they also have adventures with teams from other worlds and on other worlds. They get to see where Earth can head or where Earth can destroy itself. This would be different and if done in a thought out and logical way wouldn't jump the shark.
ONE word of advice: The vast majority of Sci-Fi people like to see a positive future and people who do the right stuff. So far, you're off to a GREAT start in this direction. PLEASE DON'T CHANGE IT! (We also like ot think beyond Earth, which is why I suggest thinking outside the Earth box.)