Here's a slightly meta question: are fan theories like that worth any consideration at all? or should they be about as cogent to discussion as Veers-Piett slash fanfiction?
Depends on the theory. 'Rogue group never had another rogue one' generally is a good one for example, since it ties R1 and ESB together in a delightful way and is something that is pretty plausible. "The old guy on the Endor team was clone captain Rex" is another good one (and with Filoni having posted stuff in relation to it, might end up canon)
But ones about a characters hidden motivations, or trying to explain 'what really happened' in a fairly strait forward scene, need to be taken worth a huge grain of salt because they rely heavily on personal opinion and usually require major changes to other established setting info.
They can be fun to discuss, but don't take them too seriously, because you can bet the writers aren't.
I mean, as much as I enjoy the "korkie kryze is actually Obiwan and Satine's kid" fan theory, I highly doubt we'll get it