To Credit with Warmech, he is a nasty below the belt random. You're walking on this big bridge, fighting run of the mill enemies...then suddenly he comes out, and your team takes a NASTY hit. Beating him might not be so hard, but getting past him without suffering some losses, a big deal in a game like FF1 where MP is very limited, and Resurrection is scarce...well, it can totally fuck you up for when you face Tiamat. Its either face Tiamat with a neutered team, or leave this big ass dungeon, and come back fully healed.
The Origins version of WarMech was pretty much the same deal, though Origins may have let you save anywhere, so being slammed by him out of nowhere wasn't so bad; save, reset, try to get past without fighting him.
Dawn of Souls just made a complete mockery of it though; your team being relatively stronger (Soul of Chaos shrines BE DAMNED), *AND* you have such a deep pool of resources (not to mention Phoenix Downs were added in), Warmech is really just a rare enemy with massive EXP and Gil rewards (not that the latter is going to matter AT ALL), who can occasionally drop some really kick ass armor!
...did I ever mention FF1DoS is such an insult to FF1 in all difficulty related ways? Even if Warmech himself was overrated, the fact that he got demoted from "Below the Belt Random that can do some crucial blows to your team" to "Durable Random you'll have no real troubles beating" really says everything (...well, no, I think "Kary's Physical just 2HKOed my Fighter WHAT THE FUCK?" getting turned into "Black Mage gets 3HKOed" is a better example >_>)