the good part is: DS is a very balanced game. the better the opponents are, the more weapon choices you find and the more playing styles. i like this fact but it could be even better imo.
second chance: the first thing I don't like is the second chance miracle. it's simply overpowered since no one choses it because it would strengthen their playstile or tactic. its simply good vs everything on every build. the only downside is six points in faith which doesn't fit on some builds. it has a infinite duration and only two slots cost while it is the best miracle in the game. the only counterargument could be that overall the game is balanced since everyone uses it. this argument is only true if you look on the overall balancing. but its false if you look on the "balancing of features" (a more or less common term among gamedesigners). if you want to have a variety of tactical choices and playstiles, then you have to make features (in this case miracles) that are equaly strong in their dimensions. in this case its either: mp cost, slot cost, effectiveness and duration. i would say mp and slot cost should stay the same, but either duration (maybe a 40s duration) or effectiveness (lets talk about 10-20% less health recovery) should be lowered.
polearms: these weapons (we talk about mh and sais) have less disantvantages than every other weapon. they are on par with damage, have a huge range, break guards, and are fast enough to stunlock. the drawbacks are a narrow attack arc, heavily rely on R1 spam (since R2 attack is crap) and they are easyer to parry than many other weapons. but we only are talking about a slight imbalance here and not a huge advantage over other weapons. they are also easy to use because the only thing you want to do with them is R1 spam and occasional pokes, which is probably the reason why some people think its a "noob weapon". a very good solution to the mentioned problems could be slightly lowering the effectiveness of the R1 attack and slightly increase the effectiveness of the R2 attack, which leads to a more intelligent gameplay.
firestorm: the fact that you can oneshot someone with one move is ridiculous and lessens the coolness of it alot. the drawbacks of this spell are manacost, slot cost and the fact that you can avoid it. This spell is designed to be fearsome this is why i only suggest to slightly increase the casting animation.
now i mention some underpowered features:
blunt and fist weapons: insanely underpowered. a never saw someone using them with success against me. those are the only type of weapons that are (almost) not used in the game, and I think thats a bummer. they are hard to use and dont excell in any dimension. one possibility to improve them could be adding something more or less unique. for example they could drain more stamina from your opponent if you hit them.
recovery: why would anyone want to use this spell if he could heal himself with grass? to have a tactical advantage over grass: there should be a secondary effect such as decreasing recieved damage by X% for a short time.
bows: in pvp you waste a weapon slot if you equip bows. they are too slow. you can only hit pigs that are stubbornly charging you while you roll backwards and get a few shots off or if you play 2on1 and the BP is stunned, but then everything is good… IMO bows should shoot faster and deal less damage to have any use in pvp. OR there should be a 2 slot buff that makes them simply faster.
feel free to discuss the mentioned features and to add anything that could be changed for a even better pvp.
and again: DS pvp is allready insanely good balanced for a game of that type!