Well in terms of the meta, actual gameplay, itemization and objective priority, it's quite a bit different. Toxicity is heavily monitered now with people losing accounts left and right, I'd argue there is much less toxicity than S3. I hardly have intentional feeders or trolls. Dynamic queue has dumbed new players down, allowing them to play only two roles, mainly one instead of needing all 5 prior to it. People play a lot more for kills due to getting an S and getting that flashy mastery emote. Snowballing is a bit more rampant now, and building tanky trumps any other build no matter what character.
In terms of new champs and balancing, it's questionable sometimes. I'd say they're trying to shift from creating front-loaded power champs that are always heavily broken on release due to how imposing their kit is against an inexperienced populace (Think release Ekko or Rek'Sai). They're now trying to create unique, but more balanced champs on release due to the anger of the cash grab of OP release champs. These champs are ones like Bard, Ivern, Aurelion Sol, Kled. There is the fact, though, that their kits just completely out-design older champs. A champion like Warwick or Master Yi have shit-boring kits compared to someone really unique like Kled or Ivern. However, these older kits tend to have a lot of front loaded power to roughly balance it all out, think Annie and her WTF combo.
They're also slowly revamping the old champs. Whether it's full reworks like Poppy or Taric, or QoL changes like Annie (Tibbers) and Vel'Koz, they're modernizing what they can. These class updates are really helping the game. Juggernaut revitalized big bruisers, ADCs brought back trashed marksmen, mage update did wonders, and I'm sure the assassin update will be great too.
Overall, for a veteran, the game is falling. For the new player, it's getting better.