The best source of soulstones is SSP, and good luck doing it without PvE gear. The fact that an opposing faction is allowed to intervene is very minor
The distinction that needs to be made is in the gearing
Arena PvP is bolstered and gear independent. It is strictly PvP, with no involvement of the NPCs. It is a very distinctive playstyle.
All other activities in the game are based on the PvE achieved gear, and you can only succeed if you are PvE geared. The best source of soulstones is SSP, and good luck doing it without PvE gear. The fact that an opposing faction is allowed to intervene is very minor. Play on a dominant faction on your server, and it is a purely PvE battle.
Now, the threshold to get rewards in SSP is so high that in this game where going for 40 min without earning anything is not acceptable is a horrible, horrible, horrible thing, but what can you do. The SSP is designed to only give more to those who are already geared, while barring those who are not, and that's the main flaw of the design.
That's the usual dilemma: to get BNS Gold you need gear, to get gear you need blade and soul gold. SS are also the cheapest commodity compared to all other million mats you need. If you are a consummate PvEer, you can run the dungeon with your friend, and split stuff like Poharan's perfumes and Machismos and get the soulstones.
You'll be getting what you want and doing what you like. You have far more options in the main stream gear than an Arena player (or anyone w/o the mainstream gear ).
Now, if by saying you are a PvE'er and meaning you prefer a solo/small party play that does not run the dungeons either, well, this game is not going to let you gear up too far on that, so, well, just do what you can.
Seriously, if that was instituted, than every other material should be tied to the OW PvP or arenas as well.

Apr
Blade And Soul VS Guild Wars 2
BnS is much more linear than Gw2, with far less content and quest variety. Nothing interesting to do besides fight, but the combat system is amazing so it's playing to it's strength there

Jan
Blade and Soul Money - a real Problem while leveling
and seems to be a MASSIVE problem in Blade and Soul, and that is Cash. Nothing gives you Blade & Soul gold, like almost nothing awards you any substantial amounts of cash.

Feb
I'm loving Blade And Soul
Arbitrary Unable to trade items rule: Some weapons are, some weapons aren't, some items are, some items aren't, I haven't found a rhyme or reason to it, to be honest.

Jul
Blade-Soul.com Review - Is Blade-Soul.com Legit and Safe?
Blade-Soul.com is professional world of Blade And Soul Gold company. their service is discreet, and Blade-Soul.com take your privacy seriously.

Feb
Now the problem for blade and soul melee mains is this
The way to obtain the majority of your soulstones also changes, the daily quests in the 50 cap faction area continue to give them but they're also very tough and near impossible to solo or even do with a small group.

Feb
A Non-Moany Warlock post
The truth is they put it at the end of the preview video... and the community didn't respond to much... They already said multiple times that they have it ready ... they just need " to press a key" and it can be in game