Okay, some proper feedback after buying her from Day 1. Throwing multiple forma on her and using her during the majority of my Orb fissure runs.
Before reading this input. Know that for beginning players, that barely have any mods and working their way through the starchart enemies, this frame does well enough. It's only when you get to higher enemy levels, compare to other warframes, or seek more utility, that the problems become more apparent.
Balefire: With how slow it fires, the status chance should be higher. Everyone is asking for crit stats on it, I don't think that's as important. The damage is extremely high and does fine already, in my opinion.
Pillage: is great. As others have pointed out however, it has almost zero effect on infested enemies. That's an entire faction where an ability doesn't do anything. It also has less effect on low level grineer units (not much armor to steal) or when the squad brings armor stripping abilities or multiple members bring corrosive projection.
The damage from her 3 and 4 (Haven/Aegis storm), is barely noticeable on enemies after level 50. In my opinion, the damage could be completely removed from both abilities and they'd be better off. When you play at higher enemy levels, the extra drain is a burden, when you don't see much utility from the extra - but low damage output.
Aegis storm: I have two major problems with this ability (as a more "Veteran player"). One, the viability of crowd control as a solo player. Two, the inability to use any weapon aside from Balefire while it's active. IF, you're playing solo or far away from your squad, the crowd control aspect of this ability sucks. You can barely move while using it, the base radius seems too low, you can't do much while in this state, after "uncasting" - enemies recover about the same rate you do. The crowd control aspect only works if you need to stall quickly for time. There are many other Warframes available, that can hard CC a crowd of enemies and still be mobile, while also using their weapons. Rhino's stomp, Nezha's spears, Vauban's bastille, Frost's avalanche, Khora's Strangledome, Volt's discharge. While these abilities don't provide energy orbs for teammates, they do allow the frame to stay mobile and use their normal weapons.
If I could suggest some changes: Balefire - increase base status chance. Pillage - give an effect when casting on infested enemies. Haven - remove enemy damage or decrease the drain per enemy in some way. Ideally, have it provide some additional crowd control in some form. Aegis storm - allow other weapons to be used besdies Balefire. After de-casting, force enemy recovery to take at least 2-3 seconds longer than Hildryn to provide some crowd control when playing solo.