What is so good about the gate spell?
I tell you what I would rule: In Darksun a gate procures only elementals.
In Eberron it could be about anything even from the far realms.
Those two, because of the "altered" cosmology
In planescape gating something into Sigil which some major force there does not want to be there, could spell a swift sure and very messy TPK for the party.
All of the above is from (previous editions) "RAW" Lore, prove me wrong but leave out 4e please
Everything coming through has the potential to be countering the wil lof the caster / casters party so what is it people like about it?
Is it the uncertainty?
I tell you what I would rule: In Darksun a gate procures only elementals.
In Eberron it could be about anything even from the far realms.
Those two, because of the "altered" cosmology
In planescape gating something into Sigil which some major force there does not want to be there, could spell a swift sure and very messy TPK for the party.
All of the above is from (previous editions) "RAW" Lore, prove me wrong but leave out 4e please

Everything coming through has the potential to be countering the wil lof the caster / casters party so what is it people like about it?
Is it the uncertainty?