I must confess, the first time I saw Janick live I too was a bit put off by the prancing — quite a contrast from the ultra-cool Smith stage presence.
But it didn't take long to get used to it.
More to the point, look at what Gers does bring: the rough-edged solo style that injects an element of wildness that maturity has tried to gnaw away from Maiden; the gothic touch to some of his riffing; and — most importantly — some killer songwriting.
Add in the fact that he just seems to be such a laid-back, class-act gentleman, well let's just say you'd have to be close-minded fool not to want him in the band.
Just as an addendum for those not keeping score:
Be Quick or Be Dead, Wasting Love, Lord of the Flies, Man on the Edge, Edge of Darkness, The Unbeliever, Ghost of the Navigator, Dream of Mirrors, Out of the Silent Planet, Dance of Death, The Legacy, The Alchemist, The Talisman...
Think the band would be better for not having those tracks in the catalogue?