Return of Reckoning

Pretty much the title.

Is it possible to increase the number of slots for mastery build switch?

Whilst five slots are nice, it can end up not being enough for, for example, a tank (applies to other careers as well): 1 slot for PVP SHIELD, 1 slot for PVE SHIELD, 1 slot for FORT SHIELD, 1 slot for SOLO 2H, 1 slot for 6MEN 2H and that's 5 slots already taken, with other builds left out, CITY SHIELD, SOLO DPS SHIELD, PVE FARMING and others.

Can and might it be increased the number of slots?

Use the warbuilder add on. I don't know ow if it has a cap on saves. I haven't run into it yet.