The aghs aura from Borrowed Time has no visual feedback on affected allies whatsoever. This is a disadvantage for both, allies and enemies. Allies may forgot about the aghs and don't realise they are 50% more tanky now, and enemies may not notice Abaddon having aghs and overcomitting on his team.

Here is an example of effects which could be used (using already existing effects from Borrowed Time)

I replaced Drum of Endurance's visual effects with abaddon_borrowed_time_h.vpcf and abaddon_ambient_mist_b.vpcf. They are clearly visible, but not too much and can directly associated with Abaddon, so it would be easy to tell that that hero is affected by Borrowed Time aura. The aura only lasts up to 10 seconds and it has a strong effect, so I think it can be a bit flashier.