This arc is supposed to get improvements to the raiding system in short order. As in over the next few weeks and months, you'll have a series of releases that add new features or change things. Probably bug fixes followed by small features and additions to the world map we get in fort mode. And yes, we might get a version increment to 0.45 before the myth arc starts. This was stated by Threetoe:
Instead of waiting months and months, Bay 12 will be squashing bugs and improving dwarf mode pillaging and adventurer mode. Don't forget! After some months of this the myth generator is next!
Also from the front page on 12/15/2017:
As usual, I'm going to be starting with the worst new issues on the tracker before we get to old bugs and small suggestions/features, but once we get there, we are planning to take advantage of the new world map screen in fortress mode, and to clean up the basic adventure experience, and much more, before the myth/magic development finally begins.
If levelling up during raids is not a suggestion yet, maybe you should post it in there. Or make a bug report about it, I think it falls under that category. This should be picked up during this cycle.
Raids and the new map in general is all part of 'things to be improved' during this cycle (provided all the identity bugs are dealt with, I guess) so hopefully it'll make it in. And yeah, no skills yet for raids. That was mentioned when the release first hit.
What is a cycle? Are you hoping to get improved raids during v0.44.x, or is this not expected until something like v0.45?
The release cycle means you get a big feature after a long wait (usually six months to over a year of no updates whatsoever), and then get smaller features added. Usually some weeks of quick releases (we're through 5 small versions already) and then on a monthly or so basis (each one followed by rapid release of short term bug fixes and so on). Then they move onto the next big feature and the cycle repeats itself. This cycle is the artefact release, next up is myth and magic.
While some of the material for the myth and magic release is yet to be planned (again, according to the front page), the myth generation system was created and tested over the last year or two as a standalone item. How quickly this gets integrated into the game depends on the code.
Link to example of standalone myth generation from early 2016:
https://www.youtube.com/watch?v=v8zwPdPvN10&feature=youtu.be&t=12m36sApparently, the magic in the world will be shaped by this world generation.