I know a lot of people who didn't even make it to lvl 30, they got frustrated that from lvl 16ish they were facing 30s in normal games
This is a rito match making problem, not an XP problem, and adjusting the XP isn't going to change that.
Let's think about it for a second. Your friends are NOT going to get additional IP from matches, just XP. This means that players will reach level 30 faster (I believe rito said that it's equal to about level 15-20 now), but have the same IP as they did when they were level 16. So now, MOST previous level 16 experienced players are going to be playing MOSTLY level 30 players. These level 30 players aren't going to be "new" level 30 players only. So there's a very very good chance those players will have full runes.
So essentially they took an XP system that matched an old system few level 16 player with levels 30s mostly when the level 30 player was playing with a friend (or if the level 16 was really really good smurf and had extremely high norm MMR) and replaced it with a system that matches the vast majority of old level 16 players with level 30s....while keeping the level 16 players at the same IP amount for runes/champs. If you plan on buying any champs, which most new players just randomly do without thinking about "I might need runes later", you are going to reach level 20 with no IP to buy runes, and you're going to very quickly hit level 30 and be matched against players with full runes that have been playing for a long time, and potentially very good if they don't play normals often.
Trust me, if you're friends thought it was rough before, they are going to hate it when they get back and have to be a true level 20 player that is suddenly level 30 getting matched against silver ranked players. I'm level 14. I've played the game before (forgot pw and it was linked to old email so I couldn't recover my account), so I'm better than the average new player. What that means is that my MMR is higher than the average level 14 player and I STILL raaarely get a level 30 player on my team or on the other team. It's typically only happens when I play at crazy times, like this morning at 6:30 AM, when the player pool, and especially new player pool, is low.
Like I said, the only people this actually benefits are smurfs and people that are making a new account because their main got banned. Neither of which should be catered to when it negatively effects new players.