Alpha Wolvers (and their subspecies) should have the ability to call for additional Wolvers if they are seriously injured (they would probably howl) to make them a bit more challenging. The number of Wolvers called would vary for each tier (1-2 wolvers for tier 1, 2-3 wolvers for tier 2, and 3-4 wolvers for tier 3) and the chance for them to do this may vary for each tier (30% in tier 1, 40% in tier 2, and 50% in tier 3).
However there is a significant drawback in this ability, as this will leave them vulnerable to any attack. Also, knights can interrupt this ability while the Alpha Wolver is calling for help by attacking it (unless it's finished calling, of course), thus preventing it to call for additional wolvers. For balance, Alpha Wolvers may only do this once. Still, the devs should implement this to compensate for the nerf they did to the alpha wolver, and this would make the alpha wolver(s) a challenging adversary (they are based on wolves anyway, so why not implement this?).
no, this wouldn't change anything because of the health they have. since they have more health than normal wolvers, they last longer than their bretheren, and so they are the last to kill and since you can interrupt this ability with any attack, they won't be able to use it ever.
and then there's the fact that we are talking about summoning wolvers. wolvers aren't a threat at all.