Your tone is unneeded. I almost walked away from the discussion rather than reply.
My tone, I thought, was absolutely spot on for someone shocked and horrified that someone would have kobolds outnumbering PCs.
First off, the difference is one of encounter difficulty and balance. The 8 kobold fight was a same-level fight. In fact, at 475xp it was lower than the threshold and could have had an extra kobold minion brining the total to 9. Likewise, in Keep on the Shadowfell there's an 11 kobold fight that's also level 1 a couple encounters later.
Meaning that the Kobolds are turning out the warrens. The first fight has what? Five minions, two level 1 kobolds, and a level three dragonshield? Or is it one level 1 and two level 2s? And the second has eight minions and three level 1 kobolds?
Level 1 fights in 4e are not designed to challenge. The PCs are all but assumed to win, and potentially win without using daily resources and few healing surges.
A quarter of resources isn't a significant challenge either.
They're designed to be able to chug along and have three or four fights after. You're meant to go hard until Irontoooth.
Keep on the Shadowfell is a crap module. News at 11.
But from story reasons, you get the impression kobolds like 2:1 odds so they can win, which implies it shouldn't be a fair fight. Not the easy odds of a 4e fight.
They think they can win against 0th level warriors (the default), not first level adventurers (significantly tougher).
Plus in 3e and 2e kobolds are roughly one-hit wonders, not the elite forces that are 4e kobolds. While they have a greater chance of dropping a hero with a lucky strike, they're little more than minions themselves.
I don't even need to look at the module to tell you that if there were eight kobolds in a level 1 fight and it was an EL 1 fight
at least half of them were minions. In fact between your two fights above, I believe you have thirteen minions to six normal kobolds.
Putting a group of L1 4e PCs against L2 minion kobolds doing 3x damage would be similar. I still don't think 8 or even 10 would be a challenge.
8 minion kobolds doing 3*damage? That's 8 kobolds doing an average of 15 points of damage each. Just about any PC is going down in two hits - and +7 to hit vs average AC of about 16 or 17. Assume one dead Kobold before they act (the Kobolds have good initiative - high dex). That's three and a half hits the kobolds get in reply. Either one dead PC (negative bloodied) or one dying and one bloodied in round 1. If the Kobolds have surprise we're looking at two downed PCs of the Kobolds' choice before the PCs can act.
Yeah, this is going to be a challenge. Especially if the kobolds manage to gank either the controller, the leader, or both.