Me for one agrees with GW Swicord. I'd do stuff just because itfits my channelor (as long asn't cost me TOO much). After all: waht the fun in winning if it doenst get you any "feeling", its just mechanical?
Besides it COULD also work in SP en MP. One channeler "spies" upon another and sees "your opponents fortress holds an considerable amount of barely restrained raw power" as an indication someone might have set up something nasty. Or "[geoff] radiates much personal power but little seems linked into his surroundings" for someone who has little invested in death effects (or city enhancing magic or...)
You'd have to play with it in beta to see what works.
This way swicord could have its way: It's potentially unbalancing - both for the player maintaining the thing as for the world when it is finally released. Thus creating all kinds of interesting tension.
So I Partly disagree with kenken and 2xpigeon: If it can have a deterring effect (because of uncertainty) it might just serve enough in-game purpose to be worth it. Pigeons suggestion that death effect magic could be cheaper would also help with that: after all, it is a wellknown fact that if you do not require your own survival inflicting damage suddenly got a whole lot easier (again: balancing to be done in beta: you dont want infinite standoffs)
I know it works: I used the tactic often in Master of Orion 2. Being Psilon (or other creative race) if you got to a technological advantage you could scare the others by sometimes wiping out a fleet on his side with an obscene omount of overkill...leaving him to fear where else you might have such superships. While in effect you only had, and could afford, a measly few of them (simultenous assault on several planets might have very well destroyes you because that super-fleet could only be in one place at the same time)
thinking on: Perhaps you could death-curse with "unbound" magic. That is - the more power you keep tied up in yourself, not invested in other stuff, the more you go out with a bang (when you are no longer there to contain all that energy). It could be very disbalancing and cool - but you couldt keep it up all the time because uninvested magic does no good - again nice balancing options.