The Capstones in the Resolve Tree are SEVERELY Undertuned
Let's get right to the meat of it. Grasp of the Undying provides very little defense (at 3k health it heals you for 90 and at 4k heals for 120). It's 100% a damage upgrade in a tree of defensive options. Strength of the Ages provides 800 gold from the health. Compared this to Warlord's Bloodlust, which provides 825 gold from the lifesteal and 600 gold from the attack speed. Or to Fervor of Battle, which at max stacks at level 18 is worth 2880 gold at max stacks (which isn't hard to get in a team fight.) Finally, Bond of Stone (which I think is the best of the three) has a very situational activation. In addition, this capstone has little to no use on tanks or fighters that are more dive heavy and do not like peeling. Overall these 3 capstones are very underwhelming compared to the offensive capstones. This has been an issue with the defense tree compared to the offense tree for the past 5 seasons. I respectfully ask that you reanalyze these abilities and improve upon the ideas which are a good basis.
If you want my personal recommendation, I'd suggest increasing the heal on Grasp of the Undying by 2 or 3 times. As for Strength of the Ages, increase the cap, increase the healing, and/or rework the ability entirely. Bond of Stone is, IMO, not too bad and can possibly be kept as it is. However, a slight increase would be welcome.