Man.... do we have some differences of opinions. Generations' 2.5 stages were only a half step towards what people actually wanted. They were great at the time when that was all we had, but in terms of old Sonic game fans, we wanted gameplay faithful - or damn near close to it - versions of 2D Sonic levels with Classic Sonic. It's like... why would I ever want some half-assed lip service?
And why would I want something that simply uses the IP name, but is something totally different like moving into a new genre? That's like Xbox360 era Syndicate having feck all to do with the old Syndicate game(s), and to my opinion is just slapping customers in the face. Case in point: which was more well received, and spawned it's own sequel line, XCOM Enemy Unknown (turn-based gameplay like the older games, given a modern graphics overhaul), or The Beuro: XCOM Declassified (genre shift that might as well have been a new IP, but they wanted the cache of the old name despite it being not the same gameplay as the old games)? I'm willing to bet that XCOM Enemy Unknown is the more popular title. Just like Sonic Mania was the best selling Sonic game of the last 20 years (or whatever metric was touted after it released).
You tell me Streets Of Rage, and I want Remake 2, not the anime visual-style of SOR4. I see artstyle like that a dime a dozen in any number of slapass indy titles.
The way to do it is to have a dormant IP, and do a left hand/right hand kind of deal.
- In the left hand you have the gameplay and visual artstyle faithful new game on modern hardware. Golden Axe 4 for the sake of argument, as a 2D scrolling beat 'em up.
- In the right hand you have some genre-switched attempt at modernizing an old IP. Golden Axe-Souls, for the sake of argument.
If you're really lucky, you get a mega successful relaunch of an IP, and two new timelines of games to follow-through with. Maybe you tick-tock the releases each time. But overall I bet you'd have a lot more happy customers. No one feels left out. And specifically the old fans, whom I assume you're trying to leverage their nostalgia anyway or else why reuse the IP, they don't feel like a slap in the face because they got a new Golden Axe game, but only in name only. No matter what avenue you want to take the game IP down in the future, you always gotta cater to the oldschool fans of that IP, or else you're ultimately going to fail. (See: Golden Axe Beast Rider)