Having compatibility with a known schema has the advantage having additional security if the wallet development abruptly disappears or some bugs appear making temporary unusable the software.
It is also more flexible if I could use for ex. elektrum and combining sometimes with gocoin just generating the seed containing my coins.
For example armory is a little bit heavy but I can generate a tree quickly from my seed with a brainwallet(for ex. brainwallet.org supports it), receive payments on the generated tree addresses and later I could import the seed in armory.
A different, new schema could have sense if presents some advantages which balances the lack of compatibility.
I have the wallet's type in the config file (so far only 1,2 and 3 are used) and I can add other algos easily.
I wouldn't mind adding new types (compatible with armory, electrum, or anything else), but the main problem is that none of it seems to be documented and there isn't really one established standard for it.
The HD wallets might be a good way to go on with a standard, though they don't seem to cover the calculation of the initial vectors from the seed password.
So it is an open topic and I think the software will eventually evolve to support other types of deterministic wallets, but I just don't want to add any new types without some strong user cases, because it would only create more mess.
But the code is open and fairly simple, so if anyone wants to put in his own method, just play with the function make_wallet(), in file gocoin/wallet/wallet.go
It is a dangerous place to play with, so feel free to post your changes here for an audit.