In theory, if I where to add an easily avalable hotter cam to an average engine, say a 500cc twin, what sort of other changes would I have to make? Obviously some carb tuning such as jets and such, but if there anything else I'd need to think about? As far as I can tell it'd just be carb tuning but I thought I'd ask here first just in case. 

I don't know what your talking about - but now my work computers search history includes a google search for 'hotter cam' and the results weren't about engines.......

hotter cams are really for top end performance, you'll kill any tractability at low speed.

Unless you live in the countryside and can keep the bike on cam it'll be a pig to ride around town.

better with airflow - exhaust, porting/polish, carbs and ensure the ignition is spot on