cubingawsumness
Veteran
The S2L method you describe is used most famously by Balint Bodor, the current average WR holder. So obviously, it's possible to get fast using this method! The other common way to do S2L is work clockwise/anti-clockwise round the puzzle. So after F2L, I would place the remaining two edges with purple (orange and light blue), and then make the 3 CE pairs adjacent to them (lightblue/darkgreen, lightblue/orange, orange/darkyellow). Then i would place the last dark yellow edge and the two pairs either side of that. Repeat for the last blue edge, and then solve the last two faces (many strategies for this). Don't worry about the number of steps, and you don't always have to define your steps so strongly on a puzzle like mega which has many degrees of freedom - if whilst making a ECE triplet, you see one of the pairs for the second step 'pre-made', then stick it in!
As for solving the same colour order in S2L, you may miss more efficient solutions if you only solve the same way each time. However, it's much easier to look-ahead if you know which pieces you are looking for at any given point in the solve!
I hope this is useful.
EDIT: to answer an earlier question 'What do you consider to be the equivalent of sub-minute, sub-30, sub-20, and sub-15 on megaminx?' it's hard to put a figure on it because people in general don't practise mega as much as 3x3 so they are not at their full potential but as a guess I'd say 1:00/30/20/15 translates to about 4:00/2:00/1:30/1:10 on mega. (1:00 would be sub-12 and 50 would be sub-10 perhaps)
Thanks for the detailed answer. I think for now, I will keep using "my" method (do the 2 have names?).