I agree. At levels 1-5 beasts certainly tend to be behind their masters in terms of to-hit. They are still usually a bit behind or maybe at parity starting in the high heroic range, but by 15th level or so they should be pretty much a solid match for most characters since they'll have +15 for level and a +5 or so for stat. Once you hit epic the beast's bonuses all around start to get pretty crazy though.
It might have been better if beasts were more front-loaded at lower levels, but it could be pretty unbalancing too. There are plenty of subtle advantages to having a beast around at low level. By the time you start to get past 15th level you don't really NEED to scrape for a lot of pluses, but having a beast that can flank and provide CA OFTEN at low levels for instance is great, even if all it ends up doing is giving someone a +2 to hit.