Well...
Let's start from shields heirlooming.
We all know, that heirlooming shield is not common. Why? Because it has to low profit. Resistance and hp increase are OK, but:
Almost all weapons receive speed bonus.
But shields don't.
I say: make it so every shield gets +8 to shield's speed at 3rd gen. Won't hurt you too much, and heirlooming (especially slower shields) will become more appealing.
Examples:
Huscarl's Round Shield
weight 9
requirement 4
hit points 410
body armor 19
spd rtng 81
shield width 43
Can't use on horseback
Gen1= 21armour 457hit 83 spd rtng
Gen2= 23armour 473hit 86 spd rtng
Gen3= 25armour 505hit 89 spd rtng
Heavy Board Shield
weight 11
requirement 5
hit points 550
body armor 14
spd rtng 78
shield width 28
shield height 60
Can't use on horseback
Gen1= 16armour 597hit 80 spd rtng
Gen2= 18armour 613hit 83 spd rtng
Gen3= 20armour 645hit 86 spd rtng
Steel Buckler:
weight 2.5
requirement 3
hit points 120
body armor 60
spd rtng 98
shield width 3
shield height 3
Gen1= 62armour 167hit 100 spd rtng
Gen2= 64armour 183hit 103 spd rtng
Gen3= 66armour 215hit 106 spd rtng
Steel Shield:
weight 12
requirement 6
hit points 225
body armor 69
spd rtng 61
shield width 31
Gen1= 71armour 272hit 63 spd rtng
Gen2= 73armour 288hit 66 spd rtng
Gen3= 75armour 329hit 69 spd rtng
___________________________
OK, next thing.
Steel Shield. How the hell axe can break STEEL Shield? Swords, too. The reason why Steel Shield isn't common is, that it slows you down a lot (it's ok for me) but doesn't give you too much. I mean, if you can destroy Steel Shield with an axe... it's same as other shields, but in addition it slows you down.
If you add +20 to Steel Shield's resistance, you can actually fix the problem of it breaking so fast. Either this or add +100hp, but believe me, +20 to resistance will not have ANY, ANY influence on the speed of destroying it with weapons without bonus against shield. If you add 100 hp, it's another 100 hits with swords, if you add 20 resistance, swords will still hit with 1 dmg.
Discuss.