Honestly, as frustrating as it is to farm IP for those 6300 champs, I'm kinda glad that everyone has to do it. With the recent exp buffs for playing pre-lvl30 in a premade, the fresh level 30s that hop into ranked don't know jack shit about how to play the game, and it's terrible for game health. By the time I hit 30, I was a functional high bronze/low silver tier player. Now, new lvl 30s don't even know better than to avoid level 1 tower dives.
If IP came as easily as exp does now, a similar problem would happen. You would get people with MASSIVE champion pools, but absolutely no skill in any of them, and this would create the same skill vacuum at the ~silver rank.
In my opinion, Riot needs to fix the way runes work. Buying runes and rune pages are complete shit. They detract from the experience incredibly and they are 100% stale. The only real decisions I make when choosing a rune page is whether or not I need the mr blues, or if I can afford to run CDR. That's literally the extent of the customization. I think a complete overhaul on runes would free up enough IP for most players to be happy with the IP gain rate.
Edit:
I am a player that has unlocked virtually 100% of the free content (all champs, 20 rune pages, and all viable runes). Now that I only spend IP on champion shards for lvl 6 and 7 mastery (and to reroll into the new champs when they are released) I gain IP pretty quickly. You'd be surprised how fast that number goes up when you aren't constantly spending it on piddly shit like runes.