Hmm, there's different angles to consider I suppose. I do think that +10 is way too high to adjust a save by- if I ever GM one I'll probably drop it to +1 per level, or perhaps some sort of sliding scale that maxes out at +6 or +7.
I'm sort of working on the assumption that higher-level characters have better thresholds along with the higher saves. So there's a chance that they may not have to make the save at all, whereas a lower-level character certainly would, and is also more likely to fail.
On the other hand, when adding the extra sneak attack dice, even +2d6 is enough to ensure that virtually anyone will have to make an MDT save. Even if the DC is low, people are making them constantly- I guess it really comes down to the style image, whether the sniper should be doing a single shot and pulling back or whether he should be peppering someone with rounds. The closest thing I've seen to combat was Boy Scout camp, so I really couldn't say for sure.
One good thing about extra damage is that it would allow for shooting through walls and the like, though I'm not sure how "sniper-y" that would be.
A lot of this will be dependant upon the weapon used, and the modifiers. But the sniper will (presumably, I haven't sat down and worked out a bunch of combos or anything) being dealing damage along the same lines as most people who haven't taken the prestige class- they need to use the same feat chains, etc. Essentially it seems to me that they don't have the capacity to do more damage (whether or not they should is a good question, it depends on how one pictures HPs working in-game), but they can do the same damage more effectively.
Mind you, all this is just my gut response from reading the article- in play it could work out entirely different. After my experience with snipers in Cyberpunk 2020 you'd think I'd know better. When the players first asked for a "Barret Light 50" I had no idea what he was talking about. Then I had to spend time between sessions scouring the net for stats. Then, when he first used it, I knew I'd made a big mistake...
The moral of all this? Never game with psychotic gun-nuts. Especially if they know where you live.