To theme, or not to theme; that is the question

I find that it is often worth it for me to run out of theme and the biggest incentive for me is our character jacks. Imperatus is great no matter where you put him and mage hunters specificity really love Disco.

Ret is 2 themes down, once dawnguard and whatever else (probably vyre/nyss) comes out theme vs non theme's balance is going to shift.

PP has stated that they expect most lists to be in Theme eventually. They have also promised that more Character Jacks will find their way into Themes, so that might change things. Also, getting more Themes to choose from will change things. If new Themes drop for everyone, that will shake up the entire meta for a while...

As of today, I find that both Shadows and Forges are excellent skew lists. You lose some flexibility in list building but gain an edge when a very specific list onto the table (also a very thematic one but I suppose that isn't a consideration in competitive play).

Sometimes, I think the sacrifice is worth it. Forges is excellent for a Rahn Battle Mages list or a Vyros2 Myrmidon list. Defenders gives Thyron access to some of the defensive Solos he really wants. Ossyan in Shadows can scare most 'jack heavy lists.

I do not think Themes are always the right answer - or that the free Solos are worth the sacrifice of less flexibility. I do think that certain lists shine in theme, however, and I would always consider Themes if building for a tournament (possibly going one list in and one list out of theme, for example).

I play out of theme if there is a specific combo or strategy that I want to build my army around. This tends to only be worth it (from a competitive standpoint) for an assassination-oriented army, as those care more about having specific models at their disposal than they do about the free points or raw combat power of a typical theme force.

For example, I have an army helmed by Kaelyssa that has Moros and a Banshee on Kaelyssa, Discordia on Elara1, and then Strike Force and Stormfall Archers for infantry. The plan is to threaten the enemy warcaster with the warjacks and try to reduce his DEF to make him easy pickings for the infantry's guns. It's difficult to produce exactly the same effect with any of themes, so I find it worthwhile to forgo the theme bonus to put this kind of strange assassination threat on to the table.

Sorry, is there a source for this? I'd previously seen posts saying that they were aiming for somewhere in the region of 50% of lists being in theme, which seems like a pretty good thing to aim for, in terms of trading flexibility for free points.