What would I like to see?
Well firstly, I'd actually like to see the homing attack. It's all good and well for people to dismiss it because of how Sonic 4 handled it, but if you're trying to make your Sonic 4 a game which feels like it progresses in the same way the originals all did, then you'd have to include it. Sonic CD introduced the Super Peel Out, Sonic 2 introduced the standard spindash, Sonic 3 introduced the insta-shield, and Sonic 4 should include something else, and that something else should be the homing attack.
I'd like to see it implemented in a way which would suit the original style of the Mega Drive games- Megamix had a decent one which didn't look too out of place. If you've also played Sonic Advance 2, you'll know that a homing attack was implemented there very well- it never hindered gameplay, but made killing some enemies really awesome. It was an unexpected dash which just ploughed through the badnik, and if you did it well you could maintain some speed. Sometimes you could use it to stop yourself flying off the edge if the bad guy was close, and that's essentially what an additional move should be about- choice. There's never a time when you HAD to use the insta-shield, it was just there for you if you thought you needed it.
What would I really like to see? The style of the originals continued and expanded on in that 'classic' Sonic way, which from your image I can see you're doing. I'd like to see Sonic and Tails back as playable characters, and perhaps including a 'new' character. For example, having Amy as a final playable character would expand upon what Sonic 3 offered, without having to add another pointless character which wouldn't fit the original universe. Classic Amy hasn't been playable, and pre-Adventure we never really saw too much of her.
I'd also really like to see some real music. Either do it Mega Drive style entirely or do something akin to Sonic CD's.
Lastly, I'd consult some people (maybe even make a poll or topic) on what tropes there could posibly be that haven't already been covered. Each classic Sonic game introduced brand new tropes every time. I could name a few now that we didn't see: a western desert zone, a sea water zone (maybe a coral reef or something, or even an underwater Robotnik base, like the Wing Fortress under the sea) etc. Think of stuff that's original. Who the hell saw Oil Ocean Zone coming? Things that are synonymous with the message that Dr Robotnik is polluting a green and lush land would be great. Maybe a power plant exploded and decimated the landscape? Accidental Atrocity Zone? There could be chemical spillage, fire, sharp metal and spikes at odd angles, and half battered enemies malfunctioning at you. What about a zone where Robotnik teleports you to a special stage-like zone in some freak experiment, and you have to escape it as an actual level? You'd have shit like the background warping and morphing in to fish, and patterns, and flashing colourful lights with big neon signs etc.
Anyway, yeah, that's my input. Really like your concept art by the way.
This post has been edited by SpeedStarTMQ: 18 March 2012 - 02:22 PM