I don't know if absorbing dragons' souls is something you get any choice in or not, we know you can do it when you kill them, but Bethesda never said if you can choose to or not, and I don't really care, because if I can choose to, I'll probably absorb them anyway since as far as I see it, nothing is gained by not doing so, and if I kill something as powerful as a dragon I want some kind of reward, otherwise it's just a waste of time.
If I don't want to have anything to do with dragons, I'll just not kill them at all if at all possible, and my hope is that, like Oblivion gates, dragons don't start appearing until you complete a certain stage of the main quest, mostly because it's going to be annoying if I just have to stand aside and watch while dragon's terrorize cities if I don't want my character to be a dragon slayer.
In an effort to be an [censored] you completely missed my point which isn't about the main story it's about RPing of course if you're doing the main quest you would because the main quest entails being dragonborn RP does not (necessarily). RP? You know that thing people have been doing in TES games for 15-20 years or so? Giving extremely [censored] examples of roleplay doesn't help your position at all and doesn't change that TES games haven't forced the character into any particular role.
The problem with that is that past games DID force some things on you, they had to, in Oblivion, from the start, you're given the Amulet of Kings and told to take it to Jauffre, you can ignore that request, of course, and under the circumstances, one supposes you didn't have an oportunity to refuse, but you can't tell Baurus to take it to Weynon Priory for you either, nor can you go to Jauffre, give him the Amulet, and then say "[censored] Martin, I'm done working for you, you take the Amulet and find someone else to do your work for you." and then walk off. Or how about Morrowind? At the start, you're released from prison with directions to deliver a coded message to someone named Caius, you don't get any choice in this, you can't say you don't want to do it, though you can go and throw the message in a muck pond or something, but what's more important is that the REASON behind your release, it's because you appear to fulfill certain aspects of the Nerevarine prophescies, you don't know this at the start, of course, but just because you don't know it doesn't mean it's not true, nor does it mean that it's not the reason Uriel Septim released you in Morrowind, you might claim your character actually isn't the Nerevarine but just someone who happens to fulfill a few aspects of the prophecy, but that doesn't really change much, you still get some details forced upon you, details which you have no choice in. Simply put, you never got to choose your character's destiny in Morrowind or Oblivion, at least as far as the main quest was concerned, you could just choose to ignore it, I see no difference here. Sometimes, a game NEEDS to force some things on you, because it's story requires it, the fact that the series uses freedom as a selling point doesn't change that, Bethesda may say "Be anything you want." but that's only because "Be whoever you want, within the limits of what the game allows." doesn't sound quite as impressive.