Gevlon is debating weakening his guild's "no-alt" rule in order to make it easier to create raids.
In my personal opinion, I don't think that alts really help a lot with raiding. Raiders much prefer to play their main character. The alt is invariably geared at a much lower level than the rest of the raid. Consistent raiding gears a character up, and improves their skills. If you're consistently raiding on an alt, you have question whether that's really an alt.
It also breeds a little bit of resentment among the people who don't bring their alts. Everyone has alts, but why is Jane allowed to get gear and improve her alt, while Vanessa (who doesn't need anything from the raid) has to carry her?
The only situations where I would use alts in a raid is if the fight absolutely depended on one class ability (Mind Control on Instructor Razuvious) or you're a Royalty guild raid-stacking for the cutting edge of content.
For everyone else, it's extra complexity that doesn't really add anything. Indeed I think it weakens the raid if you get into the habit of bringing in alts. The best progression comes with a stable core of characters, and bringing in alts cuts against that.
The only real solution is to recruit for the roles you are missing, including bench or reserve slots and rotating people. Perhaps try a system like Pods to guide your efforts.
Note: I do think the no-alt rule in general is excessive. After a while, you generally "finish" a character, and can only improve them through raiding. A lot of people like spending the free time on playing a new character. I'm not really sure what keeping those secondary characters out of the guild actually accomplishes. But I stand by my rule of "no alts in the primary raid."