Inconveniant
You can't just run into town and all NPCS in town will ignore you.
You're constantly in fear of dropping stuff [C4].
PPl shoot first and ask questions later.
Can't use the WH (except floran).
All ur SOE's put u within ganking distance from town.
Only quests outside town can be taken.
All party drops skip you.
Can't aquire new skills on levelling up (only town NPCs can train you).
When you've finished you're exploration of going to the dark side, its ****ed tedious burning off all the excess karma and doing the sin eater quest. If you killed a few too many you've practically thrown you're toon away, unless you want to spend weeks/months burning off karma.