True, Still it will leave 3 options+ ask more on the front then 4 below and your only way to find that the others are is to click on more so this will not simplify things, you probably need an back option too. limiting you to 6 totally. Now many merchants are also quest givers so trade takes one, perhaps other services too.
I kind of like how its in New Vegas who I play now, note that they sometimes have more than 8 options so many you get an scrollbar even if running an UI mod. Noticed this after the dialogue discussion here, this was an simple side quest, you had some ways to resolve quest then details about quest.
One bonus is that asked questions is marked. And this is not only New Vegas, both Fallout 3 and Skyrim has lots of NPC with plenty of dialogue options, note that you could move around in skyrim too, however I think you was locked then the menu comes up.
Now an better system would be to have an another button as an alt button this would give you 8 options who would be enough, in the few options where its to lite you can ad an ask about.
Hopefully something like this is in but don't show up unless relevant.
In short the dialogue system is my primary fear in Fallout 4. Either limited or clunky and probably clunky as hell playing on pc.