The solution I am using is to have single units get more base Hp. I also added a Masterwork Iron Golem to Arcane Armor. I agree there are some poor scaling functions for grouped versus single units. What about adding a +Hp per level to single units in order to compensate? 

I believe that the Frog has mentioned that there will be a long beta period (after this one) of balancing where they deal with all these kinds of issues.

I think troops gain too many hp per level period. You can easily triple the base hp of units, which is just silly. It puts the AI at a disadvantage as well because it will never be as good at keeping units alive as humans.

Resoln spiders need boost as well to basic hitpoints or better scaling.

Rather than halving consider just tripling it for single non-hero units.

I like armies that are super strong because many people state armies are too weak and the game can and should we won with just heroes so don't nerf armies.

@DGB They did something like that in the last iteration. The exponential hp gain quickly caused army hp to get out of control, it also heavily favored traits that granted bonus HP. Currenly the setup is 4 for everyone. Reducing regular unit level ups to 2 and increasing bonus hp for single tile units up to 10 would effecitvely quintuple single unit hp for big units (like juggernauts that currently have no defense....). You could also simply throw in that they gain bonus hp based on a percentage from all sources.

For example: All multiple tile units recieve 50% of bonus hp from level ups, spells, city traits, unit traits, etc. Single tile units can recieve up to 250% of these ammounts. The exact values might need tweaking, but I think 150% for heroes or heavily armored creatures and 250% for Large lightly/unarmored targets would be a good start. The bonuses granted to unique world units could be adjusted even higher if necessary.

While adjusting these values on an idividual basis might take more work than a simple formula it also doesn't run the risk of becoming a runaway frieght train mechanic.

@CdrRogdan

Sorry I meant 15% from the base level 1 hps so the hp gain would be the same each time they levelled - I guess I should have made that clear.

Currently, you can have a 5 man squad with 8 hp each at level 1 effectively getting plus 50% health each time they level up as each soldier gets +4hp per level. A monster doesnt gain much with an extra 4hp per level.

I suggested +15% (of base hp) per level, which is actually very low gains and would possibly need to be higher - the point is that monsters are on a level playing field if it's equal hp gains and they start off with a base higher than 8.

Of course you could also do it your way too so long as the end result is that people want to train juggernauts, bound spiders etc too

@jon I was referring to summons, unique units etc. So an iron golem buildable by the gilden would get 6 hp per level, while the juggernaut buildable by the ythril would get 10. As I said it would require going through each unit individually and adjusting their hitpoints per level, but the effort would be worth it.

@DGB  The issue isn't only level ups although 15% of some base number is more sensible.. it is also spells, traits and city attributes.

You would never give a scion fortitude (+3hp) but on regular units it is one of the best available choices. Casting uh.. whatever that life spell is that gives 3+1 per life shard is also incredible on multiple units but terrible on champions and summons. Got some building in your city that gives +x hp? Ignoring those faction unique units becomes even more appealing. There is a massive disparity between the allowable hitpoints of single tile units and multiple tile units related to factors other than just level ups.

Even with the above proposed changages multi-tile units would have more hitpoints, but the difference wouldn't be as intense.