We definitely can't use Dropbox because it doesn't provide enough space for free and shared folders take up everyone's space, compared to Drive, where shared folders only take up the owner's space.
I admit that a git repository would be more beneficial overall, but the problem that I see with them is the increased complexity of use. We tried once to get people to upload mods to a shared git repo and it was a complete flop. Git was just too complex for most people to want to bother. Even myself, having gone through github's tutorial, found myself confused at several points (and have already forgotten pretty much everything I learned). On the other hand, Drive is as simple as downloading a program and it'll pretty much handle the rest. Documents in drive can also be opened by multiple people at the same time and live collaborated (as has been done on the planning pages).
repository distribution (git does), so anyone can work with your data without needing your permission, but your permission is needed to merge it back into your main repository; this allows for easy access: no waiting for approval before you can get started to hack on it / contributeM the distributed nature also provides you with a form of remote backups (while, should dropbox go out of business or change its business model, your data is lost)
It should be noted that the Drive repo is a public shared folder. Anyone can view the repo through
this link, although only a list of people can edit.
Also noteworthy, here's a quote from Dropbox TOS:
Dropbox reserves the right to terminate Free Accounts at any time, with or without notice. Without limiting the generality of the foregoing, if a Free Account is inactive for ninety (90) days, then Dropbox may delete any or all of Your Files without providing additional notice.
While I suppose such is likely true for Google Drive, too, the data is available on a number of people's computers, and at least a few of us are keeping manual backups as well, so I don't think that data loss is an issue. It's rather unlikely that Google would try to shut Drive down without advance notice as well.
The best change from converting to a git repository would be the revisioning. As you mentioned, git has extensive revisioning, whereas Drive's is based on time and number of revisions. More information on Drive's revisioning can be found
here. In short, it works similar to the recycling bin. Revisions are lost after 30 days or 100 revisions, but we can manually specify not to delete a specific revision. Doing so will consume space in the Drive (which is rather non-issue, though). This could be problematic if, such as Tomreyn's example points out, we want to rollback to a mistake made ten months ago. Granted, be careful in what we modify and delete could largely be helpful too. Making a big change to an existing file? Back up the original first. Branching out someone else's model? Make a copy of the original and modify that. We could always use the "don't delete this revision" feature of Drive, but I'd rather trust a copy of the file personally (the differences, however, is that the former only uses space on Drive and not your own hard drive while the latter uses space on both).
But anyway, I've rambled on a bit. I'm not opposed to a move to a git repository, but I do fear that it could be too complex for some of the team to want to use it. Either way, I'd rather we have unanimous agreement on the topic.