Why do you think MK 1 is better than SF 6? ( I'm an MK fan btw.)
In terms of story, MK is usually my go to pick.
SF6 - single player/world tour is boring, reptititive and feels rushed with crappy graphics, I would choose an actual story mode like the MK1 has over it . Online is where SF6 shines, love the ease of battle hub etc. But tournaments need some work and lack of good characters has made it get old quick. Plus no comms option.
MK1 - clearly better single player story, graphics, and other modes such as "invasion" had me playing for hours and, the fatalities and whatnot all look amazing. MK1 online versus is nice, but it doesn't flow as quickly as SF6, takes longer to queue up a match/load, ranked seemingly leaves a bit to be desired at current time.
If you do decide to venture into playing online, I think SF6 is a very good game to begin with. The simplified control scheme makes picking up and getting good at the game a much easier job. The online is quite smooth as well.
You can’t go wrong with either choice. For story go for MK1, for gameplay both are ties and online go for SF6. However, it will be interesting to see which one has more longevity going forward. I predict with time SF6 will win me back, but if MK1 can keep updating and making online better as well, and MK1 and WB need to get their shyt together. I think WB makes it worse for MK1
Overall, I'm a Tekken guy through.