At this point, any THUG Pro update is a move to compete with reTHAWed.
Levels wouldn't be concerned that much because some original TH levels can be hard to port if the engine that was used to create them or port them into a later TH game (i.e. Airport, TH3 -> UG2) is a pain to work with. Thus, with THUG Pro having way more levels available than reTHAWed, the latter has some catching up to do.
Besides the levels, reTHAWed can only support THUG Pro skater rigs by "[converting them] to THAW format (Skater1014, Sep 2024)" and having those converted models replace preexisting models, which tends to be less effective than just porting those rigs to THUG Pro.
However, reTHAWed is pretty remarkable because of it's extensive options system that allows players to toggle all known tech and fine-tune physics and tricks, and I believe THUG Pro 0.8.0.0 should aim to close that trick gap to stay relevant (FLOABW) enough to withstand the advent of Dynamod in reTHAWed. Not to mention, an update coming to THUG Pro after an entire year since the last is sure to shake some cobwebs off its public image.
As for the other choices, the implementation of CAGr wouldn't do much given it's merely a gimmick that doesn't serve the point of a Tony Hawk's game. Plus, Skater1014 already covered Classic Mode with the Fun Stuff extension. Although, Classic Mode goals brought back into Goal Attack would be a nice move, but still, most players would rather play TA or Graffiti.