I don't have enough SPS or vouchers, so not really something I am considering.
Would I, if I have had the assets? Yeah, probably. It sounds like a fair price for a max level legendary summoner and the ability also sounds useful, although there are some easy counters like, e.g. Taunt with Cleanse and maybe additional heal or immunity. Still it sounds like a better Mylor, and I would get a Mylor for that price. A max level Mylor would be probably around $2,000-3,500. Would make Waka a deal if you value the prices of Vouchers and SPS in (5,000 SPS are worth $645 at current prices and the 500 vouchers are probably around $800-1,400, so in total probably less than $2,000, which is the lower end for a Mylor).