If I had to mention one thing they should probably look at is the way they've organized the ramp up for account executives (I don't know if it applies to other sales roles also). It may have been that it simply didn't work all too well for me because of a different, personal preference/way of doing things, but I definitely felt quite overwhelmed with the amount of stuff you're supposed to deal with already early on in the process. This is something I discussed with some people that joined same time as me and it was confirmed by them also.
At the same time, I know for a fact that Hubspot has some of the best sales talent out there, so who am I to judge.