I see what you mean. Personally, I only use abilities to initiate / when I use my ulti / Prevent enemies from escaping after a fight. As such, the only ones using abilities during that period of fighting should be your teammates. You should be concentrating on using Crucible/Aegis/Atlas pauldron to support your teammates in that time. If your team can decimate the entire enemy team really fast, I would then change Crucible for a clockwork as the additional shield and armour you can give your teammates is invaluable.

Ah, I understand what you mean. I, personally, consider Phinn as a true support. His abilities are not meant to damage as a primary objective, but rather to lock down targets. For example, Catherine's first ability is primarily meant to stun and lock down opponents and/or escaping targets, with dealing damage as a secondary objective. As such, the slot used to increase Phinn's ability damage would be more useful to the team if it is used for a health item such as Crucible or Atlas Pauldron.