Is this a tired phrase? -- journal article titles that start with "Towards a theory of..."
I think this phrase should be avoided when possible: not because it's tired, but because it is hesitant and unspecific.

A title like Towards a theory of branch sprockets tells me that the author wanted to present a theory of of branch sprockets, but they didn't quite manage and they ran out of time. That's not a bad thing in itself, but it's a weak pitch for a paper. The best way to structure your paper is to think of what what you're presenting and put that in the title. Here, you're thinking of what you wanted to present, but can't.

I would prefer a title like A partial theory of branch sprockets or A fast, approximate algorithm for branch sprockets optimization. The point of a title is to let me know whether I should read this paper instead of the other 50 papers I could be reading. These titles tell me what the return will be on the investment of reading. With the Towards a theory... approach, the authors are only telling me what their long term goals are, not which step they took towards this theory, towards which theory in particular they hope to be moving, what steps still remain, and so on.