Firstly, we should go over the Soul Ripper's stats to get a good idea of the unit's place in general, which will give us good grounds to consider how it may be adjusted/changed.

Soul Ripper's Stats:
29,000 Mass Cost & 812,000 Energy Cost,
75,000HP & 75 regen/sec,
2,307 air to ground DPS,
240 AA DPS, (Only 60 range, rough..)
Personal Stealth (-600 Energy, damn..!)

When compared to Wailers, the Soul ripper is utterly lacking in stats when it comes to air to ground DPS, total health, and AA DPS. This can be expected, since all experimental units are statistically lacking when compared to their T3 counterparts.

The issue is, when one is actually playing the game, there are many contexts where one could argue that having a GC is genuinely preferable to having 32 Harbingers, there are also plenty of contexts where one could argue that having a ML is genuinely preferable to having 15 bricks; But there are very few contexts, if any, in which someone can make a serious argument where having a Soul Ripper is preferable to having 19 Wailers (5320 DPS, nearly 3x the DPS of a Soul Ripper).

Really, there are only two significant advantages that a Soul Ripper brings to the table over Wailers.
-Firstly, it can be built without access to T3 air. This can be useful if you are simply looking for air to ground DPS, but you just don't have an upgraded air factory.
-Secondly, it is not subject to taking multiple hits of AOE damage from a single AA source the same way a group of gunships would be subject to. This is something that is definitely worth considering, but we should also keep in mind that the Soul Ripper lacking damage output when compared to gunships means it will take more time to destroy well placed static T3 AA when compared to the same mass costs worth of Wailers (19 Wailers). The total HP of the 19 wailers will also be significantly higher (37,100 extra total HP).
Outside of these two advantages, the Soul Ripper appears to be simply inferior to the Wailer in every way, especially damage output. Absolutely brutal.

So how can we adjust the unit?
What can be done to adjust the Soul Ripper's place in the current game balance? When looking at it statistically, it is basically just a deficient Wailer that has a pitifully narrow context of justification when compared to it's T3 counterpart. It is, in some cases, potentially better at attacking a base with lots of T2 static AA, *that still has low enough AA DPS to allow the Soul Ripper to survive. Basically, it is only good at attacking an area with low amounts of T2 Flak. In order for this unit to become more easily justifiable to build, I think to start it would need a very serious regen buff, and probably a chunky HP buff as well. This would make for a very simple patch to the unit. The previous HP nerf to this unit removed its one single advantage it had over T3 gunships, reverting this change would back to it's original 90,000HP would at a bare minimum bring it back to it's original standing in the balance.

I would propose reverting the Soul Ripper back to it's original HP (+15,000HP), and giving it an extra 50 base regen/sec.

A more exotic buff idea

What if the Soul Ripper gained a toggle-able ability to walk around on the ground like a landed beetle (similar to the Salem's Toggle-able walking function)? The unit already has legs and practically looks like it was designed to do this at some point. I think this would be super cool, but also, this would be a very significant buff to the unit, so balancing the unit with this added functionality would become a significant piece of the discussion. Imagine how cool this would be, to be able to crawl the Ripper on the ground like a insect hunting for prey? I think it would give the unit some much needed individuality.

Overall, this unit needs something, because right now in it's current state, it is completely suffocating for a place in the meta game. Lets discuss what we can do to make this unit a part of the game!