I think it's a huge obstacle. It's the single biggest jump in mma and makes for sometimes lopsided matchups. We sometimes end up with a guy on the smaller side of 205, fighting a guy on the bigger side. When this happens at 155 it may be 5-10lbs in difference, but at LHW it may be 10-15lbs of difference, which is essentially an entire class.
As for being shallow... Yea, that's a big issue. Right now if if they added an extra class anywhere near the 200lb mark, we end up with even more depletion. It's frustating as a fan because here we are with a four billion dollar company and they can't find 15 great fighters for 205 and 265, let alone for a third fantasy division. So you're right, in the short term it could be extremely weak.
In my fantasy land they would've dropped LHW to 200 and added 215, and then started recruiting guys for both divisions like crazy, but here we are in the land of Super Fights and irrelevant rankings.