Well the old ham system is gone bye bye.
Now the only way to get incapped is by your health bar getting depleted, attacking only uses your action bar when it gets to low your unable to perform attacks untill it regens enough.
Oh a notable thing now is you cant stack things like 2 shots of vasarian brandy :( Big kick up the *****
Armour is now not just a matter of getting comp armour and thats it, now you need certifications to use different classes of armour, these certifications are got for different professions, i think Bounty Hunter gets you Assault armour cert which allows you to have composite armour, im not sure but i think other professions also give you that cert.
TKM's are no long uber killing machines, in fact they do very little dmg, they are classed as a tank and can take a hell of a beating before dying, so TKM with another dmg dealing profession = good template.
Ppl may not agree with me here but id say that ranged professions are now the best in the game.
Individuals are now very weak compared to back then no more soloing jantas on dant, in fact i gave this a try and got ganked in seconds :)
Buffs arent what they used to be, but you dont need them to hunt anymore, they give you some increases i find an adrenaline injection is very good. Theres some very nice faction armour in the game now.
Oh yeah the whole system is now lvl based :) max lvl is lvl 80.
I hope this helps a little :)