Realistically, I think its a tad slower then in a few previous seasons, hex crafting onwards, because rerolls so grossly favored high content accounts they could just instantly unlock new champions and always get a fat discount for it. and once your only champs where 6300 rerolls still gave a great discount. So folks like myself could abuse and did abuse that for champions and to keep a good pool of IP.
So higher content accounts that don't own all champs got their unlock time nerfed. how ever it is comparable to earlier seasons in the amount of time it takes to grind champions, and now it favors newer and low content players which is good imo.
It is faster for new folks. 1. Lower EXP gate to level up for shards. 2. removal of necessity to own runes and rune pages. Not having a good page on a champion meant you got handy capped, your starting several hundred gold behind your opponent potentially.
So Strictly speaking it does slows down feel like old speed of unlocks in season 1 - 3 where most folks only get the BE for a new champion every 2-7 weeks depending how much they play but newer accounts get a little help to build a champion pool and are not inherently a handicap for their team by not owning pages or runes.
End result, not really worse rate then we have seen, faster when you account for runes. slower if you had a lot of content, like runes and most champions due to the removal of rerolling. Helpful to low content accounts, more like early seasons when otherwise.
I really keep trying to get some attention by riot to address the rental system. I want them to make it so you can either buy the champion you rented with the BE discount in place, or Get BE when you use rent as an option.
Also its a bit worse for folks who game many many times in 1 day but don't play every day. And better then it was for folks who play a few games each day.
That being said first win BE can be grabbed in bots games on easy so if your really really really low on time but want to get to a new campion taking the 15 or 20 min to grind some BE off bots can pay off.
<- I like to look for ways to abuse systems.