Are custom monsters okay?

[kb1]

Arctangent said:

I can't help but feel that this sort of contradicts the rest of your post. We already have the cacodemon for a monster that's not made of paper but still mostly exists for the satisfaction of killing it - the only real reason to really find another monster for that purpose is to make sure it can't just fly off somewhere, but the revenant can be used like that, anyway.

I don't quite understand your conclusion, but I'll try:

Variety is the spice of life. There's a time and place for most any monster, standard or custom. For me, as a general rule, I find it fun to rack up lots of kills per minute, which is only possible with lower-tier monsters (according to my humble Doom abilities). But, again, every situation is different, and some situations call for boss or semi-boss opposition, which is also cool. However:

DoctorGenesis said:

As long as you do not use one of those really crappy ones that are recolored versions of the monsters BUT WITH DUAL ROCKET LAUNCHERS AND HIGH SPEED.

On a balanced level, with the standard Doom arsenal, it is more appropriate to use the lesser monsters often, as a general rule. And if a custom monster looks good, sounds good, acts good, and has appropriate capabilities and appropriate hit points for a particular encounter, why not try it?