I think I was one of those asking for a more complete conformer search feature. From what I can tell, conformer search only rotates unbounded sp3-sp3 bonds. So a conformer search on a substituted seven membered ring isn’t possible. Sp2-Sp3 bonds are also not included. For example, propanal doesn’t give you any searching options although there are two low energy conformations. So, unless I’m missing something, conformer searching is currently pretty limited.
I’m not much of a coder, but it seems that it might not be too difficult to do external coordinate Monte Carlo conformer searches as described by Saunders and Still (J. Am. Chem. Soc. 1990, 112, 1419-1427). It’s mostly file manipulation and random number generation. I think the hard parts, minimization and structure comparison, are already done.
I don’t like to tell people to do things I’m not willing to do myself, so maybe I should rediscover coding and do it myself. Short of that I’d be willing to help test if someone else wanted to give it a try.
All said, I think you’ve done a great job with Avogadro. Keep up the good work.