From what I have seen, the XL is totally unused in pvp, because it is bested in each way it can be used by other weapons. It can hex, but minigun/gatling/p90 are better, it can snipe but sniper rifles or LSW are better, it can rage burst, but pancor is much better at mid range and big guns deal more damage at longer range.
First wierd thing imo, It has a standart 35 hex bursting range and a sniper like 50 hex single shot range. So the first idee was to increase it's bursting range to 40, like bozar, which has 40 range on burst and 50 on single shot.
Second, it's not really usable as a sniping weapon because it's not very accurate compaired to the other sniping weapons. They all have the long range perk (lsw, sniper rifle, laser rifle...) but XL has accurate, which makes it hard to hit on max range, even with 300 SG. To hit in eyes at 95% hit chance you need more or less 9-10 perception and 4-5 strengh with 300 skill, don't even try with 1 strengh. So, the XL could have the long range perk, instead of accurate. This way it could be usefull to cripplers for the better rate of fire (no reloading needed) and lower damage (they don't give a shit anyway).
Third, it has a small ammo capacity. Most small guns can burst 4 times (p90, pancor) but XL is only 3 (3x15=45). It has crap damage, so it could at least shoot more before having to reload, lsw can burst 6 times and deal 50% more damage on low DR targets. Even m60 is better on paper builds, tier two weapon kurwa! I think increasing it's ammo capacity to 60 (4 bursts) would make it a better weapon already.
I think the damage is fine, the hexing damage is decent, not that it is great, but it can double burst with 10 ap, so it compensate the lack of damage. Single shot is a little weaker than the sniper rifle, and I think it should stay that way.
For those who don't like reading walls of text:
-accurate perk changed to long range
-bursting range increased from 35 to 40
-increased magazine capacity from 45 to 60
I think this would make the XL an interesting weapon without breaking any game balance.