If I'm in a group of two, assuming my groupmate is doing as much damage as me, I need not a 25% bonus, but a 100% bonus to skill learns in order to have my skills keep up with my level in the same way as if I was soloing. Likewise a group of three would need a 200% bonus. His numbers - 25%, 50%, aren't at all absurd, And even if they were there, I would still more often than not insist on soloing to around level 30 on any character that could (that or make a point of bitch ranking weak characters like necros, conjis or invokers spamming grease).

As for the flat bonus. Why not? Everyone suggests it takes too long to spam, one thing that comes up again and again is that people don't have time to play. The rate of skill learning is arbitrary in the first place, why not make it arbitrarily shorter? The 25% bonus was nice but it wasn't a different world. And that people will want it even shorter isn't an argument against that. Do I spend a total of 60 hours spamming with this character, or only 50? It's still way more than 5. You know?