I guess what would put this whole issue to bed would be for Turbine to answer this question. Is this going to be permanent? If so small guilds can go ahead and add members. I think they would if they didn't have to worry about the old system coming back and bit them big time.
I'm not favoring small guilds over large guilds or the other way around here. I'm in a small guild and the change did help us somewhat. At least we don't lose as much as we did daily under the old system. We would gladly add members if we had a definite answer to this question.
Then we could all happily be large guilds with nothing to argue about. LOL
And yes for what it's worth small guilds do have to work much harder for any gain.