Trinity is such a good warframe and I love her abilities so much, but there are a lot of problems she has caused by a bygone era of Warframe.
Passive: Trinity's passive is arguably one of the worst in the entire game. With Vazarin giving you multiple instant revives and Arbitration not even allowing you to heal a downed ally, it can do nothing in 99% of the games played as Trinity. If her passive would allow you to PASSIVELY revive enemies in your affinity range without needing to stand there, it would be such a big improvement, even if it still wouldn't do much in the majority of missions played, it'd be a heck of a lot better than how it is now.
Well of Life: This ability is awkward to use as enemies are invincible when marked. The life steal even with 200%+ ability strength is honestly just not very much. I subsume this ability on almost every Trinity build except for when I'm running disruption for the demolyst stall.
Energy Vampire: The duration of this needs to be reduced significantly. Running any amount of duration makes using Energy Vampire take ages to get the energy you need. It might be a bit of a longshot, but I feel the radius of the energy pulses should be increased to account for players not staying within spitting distance of the enemy for the entire duration, and the amount of energy should be slightly increased with the base ability only giving 25 energy per pulse.
Link: To start off, any build using 1 or more corrupted mods can neuter this ability's usability. Low range makes you need to be extremely close to get the damage from it, and low duration makes it require a ton of energy to keep up as well as needing to keep casting it. The BIGGEST problem with this ability is that it only marks 3 enemies at once which is an absolute joke with the dozens of enemies being grouped up not getting effected by Abating Link's pitiful cap of 3 linked enemies at once. Link should have a cap either 7-10 or just remove it all together.
Blessing: The main issue I have with Blessing comes with it's augment: Champion's Blessing. This augment should make it so ANY healing (including shields) from Trinity increases her critical chance. The fact that Champion's Blessing only works on healing actual health and not also from shields makes it extremely difficult to keep this effect up, and even when the opportunity arises, so many arcanes and Warframes can keep their health topped up that you don't really get the chance to get this effect.