The funny thing is that most of these previews sound like they actually disliked Generations/Unleashed and Modern Sonic's gameplay as a whole, as opposed to just thinking that Forces itself is the problem.
Instances like "Sonic only needs to be pointing towards a direction to succeed" or complaints that "figuring out how to keep running w/o being interrupted relies on getting stopped several times before you get used to the stages" are pretty hilarious and basically come from people who were never going to like this game in the first place.
And, really, the latter complaint in particular is ridiculous because you can say the same thing to about every Sonic game ever released, even the Mega Drive ones. You're not going to speed through levels if you don't dedicate yourself to learning its design and enemy/barrier placement. The first time you play through them you'll get hit by stuff you couldn't avoid on time and you'll hit rocks and other obstacles placed in order to do just that. It's how Sonic was designed since, I dunno, forever.
Of course, the whole "Sonic only needs to be pointing towards a direction to succeed" is pretty laughable, as well. Because, again, you can also say that about Unleashed and Generations, and those games didn't get half the flak shown above.
Sonic was never a game you play once to be "challenged". There's nothing challenging about the platforming in the original Mega Drive games. They were all incredibly simple games and honestly if you press a direction and just struggle along you'll reach the end of the level without much trouble most of the time. The real fun of any Sonic game is getting better at it, and mastering the levels in order to achieve better times and pull out the whole thing in speedy fashion, mastering whatever techniques the blue blur has at its disposal. If you approach Generations/Unleashed Day Levels with that mind, the stage design is pretty fantastic. See Modern Seaside Hill in Generations, for an example.
So, yeah. I don't see why I should be worried, and for ages now I've known better than to trust game journos in regards to Sonic. We don't see eye to eye, and most of the time the complaints being made just sound totally out of place to someone who actually likes Sonic games, be them new or old.
P.S: Most of these people played the introductory level and are basing the entire game on it, too. It's like assuming the entirety of Sonic Unleashed Day Levels are gonna be as simple as Windmill Island....