>1) Whenever you think something is too good or too
>unbeatable, or even if you just think a certain combo can't
>stand up to another certain combo, the best way to find out if
>and why you're wrong is to play whatever you think is on the
>strong side of that imbalance seriously.
>
>Even if you have to play something you'd otherwise never play
>to do it, you'll keep the knowledge of how to beat that thing
>for all successive characters.

Maybe. It may also be that the allegedly unbeatable class is only unbeatable when played in a certain way, and you may not be the sort of player who can (or is willing to) play that way.

For instance let's say I'm unhappy that whenever my assassin runs at a thief I either 1) get jacked and stolen from or 2) thief misses the jack then immediately flees and runs away.

So I roll a thief and end up playing aggressively, running at people and trying to attack them, and not being unwilling to take some chances against people I match up semi-poorly against. Consequently I end up dying, and my gear probably never gets to the point it would have if I'd been more conservative. Does my experience playing this thief really speak to my assassin's complaint about specific thieves? Not really. Mainly because played-by-me thief doesn't necessarily behave the same way as played-by-someone-else thief.

Sometimes when people complain about a combo being "unbeatable" what they really mean is "nigh-unbeatable by what I happen to be playing at this very moment.". And, in some cases, they may be pretty close to correct.

Also, player skill matters. Maybe a certain combo is "nigh unbeatable" when played by someone skilled, but that's not the case when it's played by a more mediocre player. If I'm a mediocre player, then putting myself in that guy's shoes may not actually teach me anything. Even if I end up dying a lot, it may be in situations where the more-skilled guy would be very unlikely to suffer the same fate.