Best week on League in a long time was the week Yasuo was disabled - oh, happy day. If only it could be a yearly event but then again, less to kill.
I played a few of the new assassins. Mains will have a lot to get used to, although a few iconic things still remain intact in the kit. Rengar will be losing his ferocity if he leaves a fight but gains tons of extra AD on every kill up to a certain number. Talon now can roll around terrain and has a super bleed effect, Leblanc is more of a mage than an assassin with what's currently out there. Katarina's as awesome as always and her old W remains when her new W (dagger) is captured, she does the spin splash so nothing was really changed outside no ward hops but with the dagger she doesn't need it.
Jungle's a lot better from the brief time I've played it - less reasons to require a leash and plants to help replenish mana, health, get vision - I'm actually liking those changes.
But, with that said, I'm very concerned that people are just absolutely going crazy over change for the sake of change like you mentioned. Remember mana potions and will of the ancients? Gone last year. This year they are changing an entire class (some assassins like Noc are completely unchanged) as they did with mages and juggernauts, and as usual there will be a couple of good changes and a few bad. Looking at their last three mass reworks:
- Juggernauts saw Garen and Darius infinitely buffed, Mordekaiser and Skarner far behind (haven't seen a Skarner in over a week)
- ADCs saw Kog'maw end up reverted, Quinn seems a little more popular and she and Graves are better top lane sometimes. I'm barely seeing Kalista anymore, and Draven also seems less popular as he got nothing out of it.
- Mage changes - I'm seeing far less Veigars, Xeraths than I ever have. Weird, as Veigar was given a nice buff. I honestly think Ryze is worse than before, and don't see him very often. Vladimir I barely see anymore after the rework, Brand is mostly entirely mid as is Annie from the buffs but are still countered by good players.
So to sum up? Juggernauts got 2 more popular choices and 2 less. ADC's overall ended up with a reverted Kog and decreased popularity among Draven and Kalista from my game experience with two of them mostly going top/jg instead of ADC, and the mage update seems to have done nothing but make them far less played.
I mean, I'd return Will of the Ancients and buff the mana section of Corrupting Potion and put Team Builder back in but they don't care!