I only PvM, and despite trying really hard, had to give up and add chivalry to my 'pure armsman' template. The difference in damage output is extremely high, and as a soloer find I need it, especially against the newer creatures.

I'd suggest looking at it, training up to a mid level isn't hard and you can soulstone it out if you decide against it, but for me it's been a lifesaver many, many times.

The other skills I've added to characters just because they fit the character - my magery and necromancy primary also trained spellweaving, since it fir the idea of a 'magic obsessed' person, not because it made the template "better". My samurai took bushido purely because he's a samurai,same for my ninja... but chivalry just turned out to be too useful to avoid