Did you played duel links when six sams was tier 1? I guess not because it was no problem having a Shie En + Enishi in turn 1 + one or two Backrow due to the drawpower. Going first with six sams was most of the time gg and shiranuis would have no chance going second
As good as turn 1 six sams could be, that also depended on have a good draw. The deck can and did brick. It also depends on what backrow Shira draw, a combo of fiendish and another trap to bait Shie En could hit six sams hard. Shie En + Enishi was definitely deadly, but not always guaranteed to get out without a good hand. If your argument is the deck is too strong (sometimes) going first to not..
..to remain limited compared to how much stronger the meta has gotten, then it's a pretty flawed argument. If you want to prove your point, battle and record video of your unlimited Six Sam vs meta built Shira's in duel room and remove limited cards. I firmly believe Shira's will still easily overpower Six Sams.
You guys arguing like shiranui players never ever brick but they do and since they need a lot of backrow for their wombo combos and NEED to play at least two cards for their summons they are easy targets for duel wield etc.