I would definitively bring it up... We know that if Alicent marries Viserys Otto will become basically our enemy immediately (per WoG), and that if things have gone like canon Alicent has become a very important part of Viserys' support system, so much, that he may choose her for that alone...
So you want me to oppose Alicent as a marriage match, but at the same time refuse to express support to our father if he does pick her? I think that is injuring ourselves for no reason. Viserys favor is far more important than Otto's.
Screw Otto. If Alicent marries Viserys, Otto will soon be on the outs because of him pushing Aegon as heir. The main issue in that scenario is to make sure that we are close to our father, close to Alicent, and close to our siblings. That cuts the ground out from under Otto's feet.
During these next few years we tour the realm, making it clear that we are the heir. Befriend Borros and the marcher houses. Visit Tarly and Highgarden, and Honeyholt, etc. Visit the Westerlands and try to make friends there, consider Tyland as a possible consort. Visit the Riverlands extensively, consider Forrest Frey and Harwin Strong as possible consorts. Visit the Vale, and renew our ties with our cousin Jeyne, support her against her cousin, make friends in Gulltown. Visit the North and try to make friends. Invite Laena and maybe even Laenor along with us to try and make sure there is friendship at least with the next generation of Velaryons (will Corlys really object to his children making friends with the Crown Princess? Ambition argues in favor of making friends.) During this period is probably when we try to achieve the goal of becoming a knight, and maybe find love.
Once we have visited the North, we move on to make trips to Braavos as our father's representative, trying to broker support for conquering the Stepstones (as Corlys will probably be doing that), working out deals around what kind of tariffs and so forth are allowed, push the anti-slavery alliance aspect. Visit Volantis and see what the situation there is, as well as checking in with our cousins.
Then we return and focus on making a good marriage (if we haven't yet), and getting on the council. We leverage our stewardship abilities to try and make allies of Lyman Beesbury and Lyonel Strong and build up our reputation as a diligent and resourceful heir. We stay close to our siblings, teach them about dragonlore and spar with them, helping them learn to become knights. We talk with our father about what their inheritance will be, and seek to make them good marriage matches. We steer them away from controlling the big dragons like Vhagar and towards smaller dragons.
Strive to position ourselves so that when Lyonel Strong dies we are named as Hand instead of Otto returning. When Viserys dies we maintain control over King's Landing and the Treasury.
What is Otto going to do in that situation? Sure he'll still be a dangerous foe, but a lot of his advantages in canon will be gone.
More signs point to it as well, like it being magical leprosy given as a punishment by the chair. We would have probably identified the cause of his curse, and fulfilled its conditions to heal him and remder it a boon. After all, if the kings health reflects the kingdoms, then a strong kingdom would grant a strong king.
Punishment that implies Viserys should not have exiled Daemon?