This may not be the option for you but you could try to find a guild with similar problems and form an alliance to get going, this has helped my guild in the past during the slow summer months (we are casuals)
Also you may want to talk to those that don't show or sign for raids find out if they need help getting ready or if they just don't feel like raiding if they don't you may want to recruit new people that wants to raid,
help people gear up it is always a good investment if they can contribute to the raids if you played with them in wotlk you should know if they are good players and worth helping for your benefit in keeping raids rolling.
Those that don't show you may want to replace them or recruit others for their spots so the raiders who do show up every raid wont feel unappreciated by having to stand around all night looking for a pug member to join also find people with morale sense to not just stay away when 9 other people are waiting for them to show so you can raid this will make the regular raiders feel appreciated
i hope this makes sense and helps i have no idea how your guild works so this is just from my own experiences.
If love is an illusion to hell with reality