I'm kind of excited but also skeptical. Open world games are not easy to make, and with a character as fast as Sonic, it'll have to be pretty big, additionally, there would have to be enough stuff in the game to keep the player busy, it can't just be a vast empty space, Sega hasn't really had a great 3D sonic game since Generations (in my opinion), Colors Ultimate was rushed (it came out as a buggy mess, but was fixed later on), Forces was mediocre (in story,) Meta Era games tended to have poor character writing, but I heard that Iann Flynn is working on Frontiers, It's kind of concerning for me that we haven't gotten any leaks, (but that's not conclusive that the game will be bad), people have been complaining about the evident use of the Forces model, (it may indeed be a stand in,) but I think that the main problem of the Forces model is that in Forces, it was about as expressive as a log. Honestly, Sega does not have a good track record so far, they have postponed the game for a year, but I'm really hoping the game comes out great.
It's a pretty big thing to pull off, as for boosting in the game, I think it's likely, as an open world game is probably the best place to use boost, not necessarily a narrow pathway, an open world game would also have less scripting because there's more freedom for players to move about, I'm interested in finding out how they'll pull off the new fighting style for the bosses, I'm thinking that we might see something like a big hubworld with entrances to the various zones, sort of like a giant version of the hud in Sonic Adventure, as that would enable exploration, and focus for the fast paced platformer that makes Sonic unique. With those weird effects we saw in the trailer, I'm guessing it might be some sort of thing where when he defeat an enemy, it gives you energy to boost. It's not an impossibility to have boosting in an open world game. But that's my take on Frontiers.