Pardon the cynical, but have you looked at the recent games in each franchise?
Skylanders isn't even known by the title of Spyro and is in essence a massive cash factory, Sonic had to make a massive call back to all the games in the previous times and still screwed things up fairly but not enough to be badly by bringing back characters from unwanted timelines and unwanted levels, and Mario games are pretty much safe with no real innovations.
Really, we may as well just mash in Tomb Raider for good measure.
I'd much rather have Mario Party upgraded to Nintendo Party. Except with Mario Party 5 mechanics.
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Yes? What is it? Ok. Now that is good.