I think Cold/TA would be a stronger PvP combo. The trick is to string together the TA attacks in you chain so you don't have to keep redrawning. The animations tend to keep you rooted to the spot though.
Oil Slick Arrow does not seem to knockdown as well as Ice Slick, I think it ticks more slowly. It can do serious damage to a target trapped in the burning oil though.
I really should do something about this signature.
It was the -slow of Oil slick arrow, I was aiming for.
Fire was to ignite the oil slick (I dont know how it works).
A Paragon Defender
Fought one the last night in sirens NB, the trick arrow powers were damn effective on my stalker, completely screwed up his movement, the sticky arrow is really nasty. -jump.
I think in the high end of PvP it'll be really effective. That sticky arrow is pretty uber, aswell as immobilze for containment and extra hold.
Matron had a grav/trick arrow and did really well in PvP zones aswell, mainly because he screwed up so many villains movement, and hit them with containment damage.
Edit: Oh yeah pretty sure i read they lowered animation times for arrow powers. Fire already has short animation times.
Funny you should ask this 
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Made a Fire/TA to, I think, level 10 to test out the -perc mainly.
Testing it out in the arena I killed an even level blaster purely due to this (low level blasters with their loads of attacks and defiance are usually tough at low level for me) score was about 6-0 purely due to -perc.
Didnt even have stealth but if you thow that in I think you could easily make them lose target while you move in and out of range and your pets beat em up, (just have to fight those nasty black widow bosses in zone mishs w/o +perc to see how nasty -perc can be, which gave me the idea in the 1st place).
The reason though I didnt carry on to see what else was on offer was the HORRIBLE anim times on TA which I think will get you killed alot 
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Edit: Also asked on boards if TA was getting anim reductions along with archery but didnt get an answer.
I played a TA troller all the way and i agree TA has some really nice features, in itself pretty good for pvp too. But the drawing time, animation times and recharge are too much imo.
Fire/TA, might work pretty nice 1 vs 1- e.g. like said perception debuff is brill-, but untill they funk up TA, i don't think it will make a good overall pvp set.
I was going over the sets to see if ther was any nice combos that seemed less used, and my eyes came across Fire/TA. Its gotta be awesome in 1on1's.
You get 2 single target holds, 2 single target immobs, An ice patch like power, 2 -perception powers, a -jump power, -res powers.
All of which are really, really cool in PvP.
The big questions is: Does the animation time ruin the combo?
A Paragon Defender