When i started using construct2 about 3 years ago, i never thought about the limitations really. I was never trying to do any complete game. I was more playing around and learning how the event sheet way of coding worked. I think the main reason for the trial is pretty much this... If you can figure out the basics of how the engine works that's pretty much what you need to make an informed decision whether or not this engine works for you.
For me it took a couple of months before I bought it I believe, because I didn't really have time to play around with it much.
I don't think the free version is intended for people to make complete games, and I don't think it should. Why would anyone pay if they could do everything they wanted in the free version? From as business perspective I don't think it would be good too have too many free users even if some of those would eventually become paying customers, but I can agree that more people needs to know about the software.
A good idea is probably to implement some social media functionality so you can earn more events or unlock more features by sharing on facebook, twitter, youtube or other social media platforms.
I think i saw that it works something like this now.
25 events logged in as guest
40 events when logged in.
50 events when account is confirmed.
So maybe a good idea to have people earn more events by doing certain stuff that could benefit Scirra, like sharing, or creating tutorials etc etc.