The basic framework I use to determine topicality is essentially about whether it's something you're encountering that is plainly arising organically from an encounter with philosophical study, reading and analysis. I've tried to articulate it in that long thing I wrote about "we are not philosophers, people". The point is that it has to be about some obstruction or vortex that is preventing your navigation through philosophy.
The issue then is that the question-problem has to be an encounter you have while trying to undertake the study of philosophy. But this is actually a philosophical question in itself -- I mean, whether philosophy has any content of its own, or is rather a process of refactoring and constructing higher-order "algebras" for everything "else". At any rate it raises the hairy old question of what philosophy "is".
I'm tempted here to point to Deleuze and Guattari's insistence that philosophy is a creative activity, that it creates concepts. Finally maybe even that philosophy cannot be undertaken even as study without the reproduction and permutation of conceptual personae. Creating concepts through pure variances is how philosophy thinks; where mathematicians and sciences think in terms of functions made up from variables; and artists and writers think, again just as much as philosophy and science, but in terms of affects: colors, sounds, textures in composition.
And all this is maybe to say: while philosophy and science may appear to be great enemies, science is maybe the greatest ally to philosophy in the war against received notions, popular perception, religious dogma and so on. There is something similar to be said for science and art. And in fact all this points to the great "outside" that each of these disciplines face, and the universal shadow that falls across them all -- cast by the glare of the future, by a people to come and an imageless thinking to come. Nietzsche dreamed of the reunification of science and art/philosophy at long last; once both had become "profound" enough for the transformation.
I mean, look -- I think we have the merest glimmers of this sort of thing today; but it's enough for me not to wish to draw particularly granular boundaries. Again the basic framework being something like: does the question specifically refer to an organic encounter with a thinker, work or idea in your study of philosophy? If not perhaps it isn't really our question after all -- though if you do happen to find a line of investigation that does connect back to problems you're working through in your philosophical study, that seems at least plausibly topical again.