That sounds like the sort of player who'd get uninvited quickly. My players and DM tend to lose patience quickly with that sort of behavior... (the latter example)I've got one of those. If he's a wizard, he studies the board for 10 minutes before casting Ray of Frost again. Then you've got the players who simply will not let anyone else take their turn if he deems their choice of action to be sub-optimal.
As for my own issue, the problem seems to be primarily a combination of truly horrid dice rolls on the player side; really lucky rolls on the monster side, and the use of finesse weapons by high dex monsters. Those +5 to hit modifiers, and +3 to damage add up. also, it completely circumvents the main disadvantage kobolds have:being weak! The pack tactics, and the advantage on to hit rolls doesn't help. Adding the dex modifier to missile damage similarly ramps up damage totals. We're talking a bare minimum of 3pts of damage per hit from a dagger or sling stone for kobolds. Even more for orcs.
Today we tried our luck with the Orc cavern. I had the area 8 orcs set up the ambush in area 9 rather than hitting the party from behind. First group was wiped out quickly, thanks to some good tactics and nice die rolls. (the crit rolled on a sneak attack by the rogue certainly helped!) The ambush was a tad harder, thanks to 1/2 cover- and they weren't able to get them all before reinforcements started arriving from the common area. Those wave attacks were pretty draining, and we needed to burn 2 cure wounds spells on the rogue and mage, before moving on. The chief and his consorts were faced with both cleric and mage down to 1/ea 1st and 2nd level slots, and none but the rogue was at full health. By the end, the cleric was unconscious, and blew his first death save! (and it was a freaking consort with a dagger that did it...) Luckily, the last 2 were killed by the end of that round, and the mage was able to provide aid to stabilize him. (I KNEW that healer's kit would come in handy!)
I gotta say, that tactical nuke known as Radiance of the Dawn that's the Light Domain's 3rd level power came in right handy- it literally saved our bacon!! Being 3 for 3 with that mace of his didn't hurt either, lol. Fighter whiffs every other swing, but the cleric has a near 100% hit rate... Gotta love those rolls of the dice!
Also, whomever gave the Light domain Burning hands, Flaming Sphere, and Scorching Ray as domain spells is just plain mean!