The value of
Insidious Dreams over another more cost effective tutor is the discard outlet and the topdeck synergy with our commander (and your miracle cards). I would think for the miracle set up alone that it would be worth consideration. It's an instant speed tutor that allows you to hit literally any ADD you want from your library, ensuring Kaalia grabs us 3 cards on her trigger. This is one of the only cards that enables this in these colors that I am aware of besides
Doomsday. Correct me if I'm wrong.
It's worth pointing out that this effect also means we will be shipping less non-ADD cards that we need to the bottom. I hate seeing key pieces getting shipped away from Kaalia's trigger.
You can also set up miracles with it turn after turn if you choose, assuming no other draw.
I would argue that we
absolutely have a need for a discard outlet. The discard allows us to put things in our hand that we don't want to have in our hand into our graveyard for later recursion similar to
Faithless Looting. At least in my own playtesting this has been the case. Simply because we have so many creatures, we have a good chance to get them in our opening hand, or draw into them when we are wanting removal but we still need a certain saturation for Kaalia's trigger. We can search for Living Death or otherwise the means to reanimate the creatures that we just discarded.
If you can manage X=4, than that means you can draw into something you really need, and also get 3 hits with Kaalia on your next turn. I could see myself getting
Astral Slide or
Sneak Attack, and three solid threats, depending on what other pieces I already have. There are many options.
Early game it can set us up to get the ramp and colors that we might be lacking, grab key cards like
Astral Slide and late game you can topdeck removal, or game ending pieces. X can be 1 in many instances. It's higher on our curve but I think the value is worth it, especially at instant speed. I don't see any drawbacks other than the cmc which is manageable.
I think you have a lot of good synergy but I agree that you aren't really able to field enough of a threat with the lower cmc creatures. While there are plenty of powerful drops at that 5 cmc mark, my feeling is that we still need a few key ADD that are beyond our established rule. However, this only really works if you can cheat them into play fairly reliably or abuse their triggers, as simply having a single fatty on the board isn't going to do a whole lot for us. I think ADD like
Angel of Despair,
Knollspine Dragon, or
Rune-Scarred Demon are worth considering for this reason and I intend to try them out.
I will have more to say when I've played more games with my own list, but I can tell you that the
Worldgorger Dragon combo and
Sneak Attack are performing very well for me, allowing me to close out a game to some degree of consistency.
A synergy that wasn't immediately apparent to me but turned out to be pretty awesome is
Doom Whisperer and
Living Death allowing me to field a bunch of creatures at once. This is great if you have some source of lifegain in those creatures.
Victory's Herald which was originally just a stand in from my binder, has actually performed quite well in this regard, although I am sure there are more cost effective options.