So you have survivability closer to a Fighter or Barbarian.
The player chose to prioritise Int over Con because they wanted to play someone who was intelligent, but not as tough. Presumably for the same reason that they chose to actually play a Rogue rather than a Fighter with a criminal background. As soon as the DM mentioned that their style was going to disadvantage the Rogue compared to purely combat-focused, resource-based classes, that would be a definite option for someone wanting to shine more in combat compared to out of combat.
As it is, the player went ahead and made the choice to play a less-combat-focused class, and assign abilities in a less combat-focused distribution.
Yes. Exactly. The Rogue does sacrifice pure combat capability for pure out of combat capability.
Just like the Fighter sacrifices out of combat capability for combat capability.
Choosing to be best at something involves choosing other things that you won't be best in.
I'd suggest you have a chat with your player. It sounds like they are unhappy about their low performance in combat and don't view their choice to be good at out of combat things to be worth the trade-off. Thus would rather play a more combat-focused character. It shouldn't be too hard to remake the character as a Dex-fighter with superior combat capability.
Your words, not mine.
Specifically, it was important to know how the player prioritised their choices: you don't want to invalidate their character creation decisions by undoing the trade-offs that they wanted to make.
Now, your suggestions (This is the bit you're probably inrerested in [MENTION=12731]CapnZapp[/MENTION]) would increase sneak attack damage by 14 points at the current level. Plus the backstab dice which I'm going to arbitrarily guess at averaging an extra 5 pts/round. (4 or 5 d6 at 9th level, split into only 1 or 2 combats per short rest, but often used on crits.)
With nothing stated to the contrary, we'll use basic 5e assumptions: The Fighter and Barbarian are probably using weapons that average a few points higher than the Rogue's and have two attacks. GWM is worth up to +5 damage on each of those attacks. Everyone has +5 ability bonus.
Rogue damage per round would be around 46 (d8 +5 +9d6 +5). 50 if they dual-wield as would be optional. Getting additional attacks in from reactions would be highly useful with these changes, but we'll assume that they benefit the other classes as much.
Fighter DPR is going to be (2d6 + 5 +5 +5) x 2 or around 44. Chances to hit should be about the same.
So: it kinda depends upon whether you regard the Rogue dominating the combat as well as out-of-combat situations is what you're aiming for. I'm guessing that it'll make the Rogue player happy. How the players who actually build their characters for the purpose of combat will feel about it, only you can tell.
Good call adding a mention.
Thank you for coming up with these 46 vs 44 numbers. They tell me my suggestions aren't far off the mark.
The point is, the Rogue's particulars scream for it to be a glass cannon. It should be able to make alpha strikes like no other class in order to justify it being squishy and have no magical tricks up its sleeve.
Ideally the Rogue class design is remade entirely, and a clear demarcation is done between ranged and melee builds. At range, the ability to sneak and hide is a clear advantage, and I wouldn't want to add an alpha strike to that class.
But in melee, where the bonus action is needed to dual-wield, and where you can't escape the monsters and can't easily hide, it's another story.
So thanks. Overall the simplification of the sneak dice (one full helping instead of two half helings) seems to do the trick.
By your feedback, I'd say the "backstab" ability needs a bit of a boost, but making it melee or thrown weapons only.
Regards
Zapp
PS. Why are you okay with the Rogue out of all classes lacking a combat-focused build?
All the other classes (to my knowledge) can be built for combat. Party-focused combat even (that is, disregarding the "the Rogue does perform well in combat, assuming it gets to sneak around on its own" argument).
Most complaints (that I've seen around here) are directed towards beastmaster ranger, four elements monk and sorcerer. But it turns out ranger multiclasses excellently with fighter, the beastmaster is the sole class WotC have conceded needs an upgrade, you can choose another monk subclass, and as long as you choose red draconic the sorcerer does splendidly (and in fact rises to the DPR top on any short adventure day, converting most low-level slots to sorcery points to twin or quicken spells or even both in the same round).
But the Rogue is expected to work its ass off, and for what? Byzantinely scrounging a second sneak out of it? That's not good enough - that level of play expertise plays off much better with any other class.
Even if I buy your numbers right off the bat, the thing is, no class as squishy as a Rogue will "dominate" combat with a mere 2 points advantage over the sturdy Fighter. What it does imo is just barely justify why any party would invite a rogue - sure it's squishy, but at least it now pulls its own weight (dealing competitive damage), and it's useful to bring along for hidden traps and treasure.
It is, after all, "just" a martial. Imo all martials need to do well in combat, since they don't have nearly the same amount of doodad magics as the full casters.