- You need 7 troop ships and can't make a 10 batch because you can't spend more PP than the strictly necessary: then you have to add at least two batches (e.g. 1 4x + 1 3x).
If you also want the troops to pop up at the same time (e.g. because you want to use the "rally to somwhere" but be sure they arrive to destiny at the same time): then you have to watch their progression and reorder them or pause one to ensure simultaneous completion. - You want to keep a certain ratio of ship designs (e.g. 1 cannon, 1 bomber and 3 chaff): then you have to add one batch for each design, carefully set their sizes to ensure all of them get PP on each turn, and watch their progression to reorder or pause some batches, or add new smaller batches for the design that is dragging behind, or change their size. And this goes on for the whole game (I mean, it is worse than previous point issue).
- You have enough PP to build 10x ships but you want to make sure you get at least part of your batches in case your PP supply gets cut: you must add 10 1x batches instead of 1 10x.
Solution for issue 1: change the drop down menu with fixed numbers for the size and repetition fields for an editable box with the up and down arrows, same we have to set (e.g.) number of systems per galaxy at game creation (that can be affected by the mouse wheel). Also, make it show "infinite" symbol when the player writes down or rolls the wheel to a number bigger than 99.
Solution for issue 2 (not that easy): Allow the player to drag and drop ship designs into an already present ship design batch, which will create a "composite batch" showing the two (or more) ship designs in the production queue rounded/enclosed by an extra box and preceded by a small tittle line with the wording "Composite batch" (or alike) and the size and repetition numbers.
The player can then move the whole composite batch up and down in the queue by dragging the composite batch title, or right-click in that title to access the common options of "move to top", "pause", "disable stockpile extraction", "remove", etc., and can remove or add ship designs into the composite batch as would be done with normal batches (drag and drop into the batch, or right-click on a item within the batch to remove it).
The items within the composite batch have the exact same appearance and functionality than the regular batches: repetitions, size, ship design name, and progression. Repetitions might not be a good idea for the items within the composite batch, I'm unsure. But size (x1, x2...) is important so that one can ask for 1 cannon + 3 chaff, etc.
The PP that get invested into the composite batch are evenly distributed among all the ship designs.
The minimum turns for all ship design within a composite batch must be equal to the maximum of all of them, so that all the ships in the batch are finished at the same time.
//Edit
Tentative mock-up for the composite batch thingy: Equation for PP distribution among items in the batch (if I got it right):
Ai = min(A*Pi/P, Pi/Tm)
where
A is total PP that can be allocated to the batch in the production queue
Pi is PP to build item i (i=1..N), considering size of item i.
P = Sum {i=1..N} Pi, is total PP of all N items in the batch.
Ti = minimum turns to build item i
Tm = max(T1, ... TN)
//
Solution for issue 3 (even trickier): add a toggle somewhere in the (composite) batch items to enable/disable automatic split of a batch, that work like this: for batches of size>1 (x2, x3...), if PP invested are not enough for full size, split the batch into two, one with size for which PP invested are enough to go at max building speed, and one batch for the remaining size.
This might be rather problematic, and I would say it is not worth trying. Like saying "Are you annoyed because someone cut your supply lines and screwed up your production timing? Be careful next time and protect your supply lines better"
Now, let the debate begin and I'll open feature requests for each one once debate is settled.