Finally got to put some testing time in so I thought I would post my two cents. I'll avoid talking about the nerfs because we all already know the losses and applications so instead I'll focus on buffs and gameplay changes for Greninja.
First, no VI makes combining much easier at low percentage, when combined with the new U-Spike you can usually rack up a lot of damage. have done D-Tilt, u-throw(it connects at low percentage), u-air, u-tilt, u smash for 40%.
His new SS is significantly better than first appears. It's a ludicrously powerful OOS option, given its range power an kill potential. But even more amazing is it can now be used to secure kills off stage, which plain couldn't have even been attempted safely in 1.0.3. Ring able to chase so far off stage helps get back some of the lost kill power, as you can go really deep with this and still make it back using a second jump and SS. It should be noted though that it takes quite a while to get used to, so practice is recommended.
Lastly, his D-smash is just plain good now. It was already his second best smash next to U-smash, but to be fair his U-smash post nerf was his all round tool for nearly everything so I can understand the shifting of power to his D-smash.
Overall he feels a little weaker, you can't really just spam your best stuff and expect a win anymore. All his moves are more situational but for the most part have their place, an he still has one of the most diverse kits in the game. I believe that SS gimping will become pretty important to his gameplay now, but as with most the time it's used don't spam it, keep using as a mix up, especially since your opponent can not see the shadow off a ledge.