It sounds like you have never experienced the Siege Golem on a Spire. In the Sound of Thunder scenario. It made me want to cry.

It's quite interesting to hear in other rounds come to very different conclusions. As Uthuk player I don't fear the Siege Golem, because he does some damage, but he has almost no board impact. Overall his inability to move and shoot makes him very unflexible. Do you have really ever moved him? To use a selection just to move 1 hex is... quite hard. And if he has no target with another unit adjacent, his attack is worse than the doubleshot of archers (2x2 over 1x4 because of different targets and double bonus dices). In the games we made, Daqan player had problems if there was a concentration on range. The simple reason, the dammage-potential is limited. Even if you take out some units before getting attacked, without you need to respond the melee attacks. Me for example, I tend to just ignore a Siege Golem playing Uthuk.

I think the Siege Golem is the most situational unit in the game, and have only used him twice (and I prefer to play Daqan when I can)... but in those two games he made a big impact. Scenario setup in both games created a board where I could deploy it in the center section where he had line of sight and range to all areas of importance, banners and special objectives. He never moved and nearly every time I had the opportunity, I activated him. Units tend to bunch up near banners and objectives since that's where the fighting is so there were plenty of hits thanks to Barrage. Best case was an enemy Wraith that was in the woods near a banner... that's a great defensive position for a Wraith since most units would only roll 1 die against it, but I was attacking someone next to him and used Barrage results to hit the Wraith.

While units bunch up in big fights that's not a problem for line of sight since the Siege Golem ignores units when tracing sight. When my opponent sent a couple units to attack the Siege Golem it stunk not being able to counterattack, but on my turn the Siege Golem could still fire on distant targets since the adjacent enemies still can't block his line of sight. But he's got a lot of health and can ignore 1 retreat so he stood his ground and held on until other units could take care of the attackers. When they forced one of those units to retreat he was now no longer adjacent to the Siege Golem so I could attack him, and apply Barrage hits to the other attacker still next to the Golem

So take a good look at the map setup when choosing your units. If the board is fairly open in the middle (less likely against the Uthuk... they seem to have more forests/hills) you might want to give the Siege Golem a chance!

I've found that you have to go out of your way to kill the golem, and that is already a purpose served. Sure, it can't counter, but having to send units past banners and into deep Daqan territory is a dangerous proposition. Add six hit points to that.