Blizzard has stated that they want all talent builds to have some reasonable amount of filler - they've stated on a number of occasions that they want the "cookie cutter" builds to be more along the lines of "take these 65 points, and the last 11 you can do what you want with". Hence, the fact that Combat has more filler means, well, it's closer to what they have in mind.
The problem, of course, is that combat filler is mostly boring from a PvE perspective - there's a fair number that might be interesting for solo play or PvP, but in terms of PvE you're probably looking at taking Imp Sprint, Endurance, and then, like, Deflection for lack of anything better. I'd say the *amount* of filler is reasonable, but it would be good to have some more interesting options. Imp Sprint is a nifty talent, Endurance is sort of okay, and everything else is either actively useless or somewhat boring. So a little sprucing up of the filler quality might be nice.
Assassination, on the other hand, has the reverse problem; there's lot of interesting talents that you can imagine wanting to take (Vigor, Fleet Footed, Deadly Brew, Imp Expose - and even Quick Recovery and Deadened Nerves aren't terrible). Unfortunately, you only have room for four points of filler, two of which need to be in the first two tiers (where there's, regretably, nothing even remotely worth taking). Hence, some talent consolidation might be worthwhile so as to make some of that filler a little more accessible. Fortunately, there's some obvious candidates:
- Seal Fate seems expensive for a 5pt talent; dropping it to (say) 3 might be a reasonable option.
- Turn the Tables is and always has been a weak talent and should probably be dropped entirely or at least replaced with something a bit more interesting.
- Cut to the Chase has always seemed odd as a 5pt talent as there's almost no motivation to ever put less than 5 points in it. It could be made a 1 or 2 point talent elsewhere in the tree with relative ease.
I'm sure there are others as well; those are just the immediate ones that spring to mind.
It's also worth noting that Imp Evis is sort of an odd fit for Assassination right now, as it's reasonably useful for the other two specs but completely useless as an Assassination rogue. It might make sense for them to extent its benefits to (say) Envenom as well, thus moving the point where you start spending true "filler" points further up the tree.
In short: right now there are 53 DPS talent points in Assassination, which require 4 points of filler to get all of. It seems to me that they want to reduce that number by about 8-10 to wind up somewhere in the mid-40s for total DPS talents in the tree, and to move a few of them further down in the tree to grand a wider range of filler options. Tiers 3, 4, and 9 in particular feel somewhat bloated right now.
The other issue that's a bit concerning is the new 45 point talents in general. Placement at the 45 point level means they will *always* be cutting into DPS talents in other trees - that is, to take Restless Blades, you're dropping Relentless Strikes or poison talents; to take Venomous Wounds, you'd dropping Lightning Reflexes, Opportunity, and/or Relentless Strikes to get it. And that strikes me as potentially concerning. Combat seems to be developing a cooldown-centric playstyle, with a fairly simple standard rotation but lots of cooldowns. Hence, it feels important to me that a talent like Restless Blades - which so clearly fits with that playstyle - actually be good enough to be worth taking. And at the moment, that seems a bit... borderline. It feels like the value proposition should be a bit more clearcut for such a tree-defining talent.
Similarly, Venemous Wounds, while a neat idea, has the problem that, by default, Mutilate would not necessarily be rupturing (given that the entire tree is structured around envenom, right down to the mastery). Hence, Venomous Wounds needs to be good enough to not only offset the out-of-tree stuff you're missing, but also to make it worthwhile to transition over to Rupture by itself. And that seems.... dubious. We'll have to wait for the final numbers to figure out whether it's worth using or not, but, again... it seems like a cool idea that could very easily wind up being completely ignored as it stands.
To be clear: I'm not saying that they can't work, or even that they don't - we'll need to wait a bit until we get the rest of the information (masteries, early itemization, etc.) to be sure. But it does seem like there are some definite questions about talents in that location that I would hope to see answers to before things go live.