Never assume things always remain as they are Vim!
Actually Selwyn are showing greater maturity at a earlier stage than Waimak, so should evolve into a serious club sooner than them (obviously well on the way already and could shortly threaten the status of some existing MPL clubs - Bays would be my pick as the likeliest candidate here). Good point about maturity actually 10cc, goes hand in hand with planning - ever lived in a house full of teenage boys? If you have you'll get my point. Never ending chaos directly attributable to frontal lobe development that means they can't plan regardless of the need to. There are parallels with the growth and development of clubs.
Selwyns websites tells it all www.sufc.co.nz , a very well organised club by the looks of it with lots going on, looks like they have all the bases covered for a complete football experience no matter what level you are at.