I'd like to go into the group who thinks pilums are just fine. Got as my starting frigate on my most recent game, the, err, I think it's the vigilance? The one that has a medium missile & medium energy slots.
And wow, does that thing absolutely demolish foes. Got a two-on-one fight? (Or three, or occasionally even four?) No problem! Just spam pilums at whatever you're not currently engaging - that'll keep it quite busy enough while you hunt down the other. Hounds in particular will spend a while dancing around, and then just randomly die somewhere far off-screen when your missiles finally catch up. Fighters? Surprisingly vulnerable to pilum missiles. Especially bombers.
The low speed isn't even an issue - anything that's busy running from pilums isn't shooting at you, after all, and it has to turn around sometime if it wants to attack...
Oh, and you don't even need a target lock - if you can't see any enemies on the map, well, that's fine; fire the pilums anyway - they'll pick something and start homing in.
Now, they may be less useful against ships with lots of point defense - for example, firing them straight at the front of a lasher is a good way to waste some missiles (oh no, you wasted some missiles; you've only got 27 more!) - but if you're getting into large fleet engagements, you can have a *lot* of pilum missile launchers - and that works out just as well.