I see your point, but I’m not sure that under these Scouting rules the Skaven list is worse off than, say, Dwarves or Empire.
In a 2,000 point army the Skaven can have up to 8 units of Gutter Runners (16 scouting points) 4 Jezzails (2) and will presumably have a hero or two (1) plus the general (1). That’s potentially 20 points, although I concede it might be low teens if it doesn’t max out on Gutter Runners. Regarding ‘lie low then erupt’, isn’t that what the infiltration rule does to some extent? And Gutter Runners can be committed to scouting without having to be placed if their army ‘wins’ the scouting.
At 2,000 points Dwarves are limited to 4 Rangers (8 points), there’s no limit to handgunners but I’ve rarely seen Dwarf armies with more than a few (1 or 2), general (2) hero & runesmith (1) and perhaps a (highly vulnerable) Gyrocopter (3). That’s only 14/15 points.
Fairly standard 2,000 point Empire army with general (1), a hero on a griffon (3), four crossbows (2) and four Pistoliers (4). That’s only 10. But given that the army usually has lots of slow-moving knights, steam tanks and cannons, getting out-scouted seems fairly realistic. In that regard, the Skaven army would presumably have similar encumbrance in the form of warp cannons, doom wheels and/or screaming bell?
Bottom line? Armies with lots of light cavalry and flyers will have a distinct scouting advantage, but the rules are written so that being out-scouted is not a huge problem. Some players might just shrug their shoulders and take more heavy cavalry instead. And, of course, there’s the random effect of the 2D6!