There have been events like the Lucky Board and Lucky Stars which have med. threads in its reward lists. These can be gained through coupon savings and luck.
I feel there's no real need to go beyond lv3 since, like you said, most f2p players will be at lv3, this creates a level playing field. However if you must become stronger than everyone else then you must look to extraordinary means to acquire such power.
I've friends who are 40-60% down the line to lv4 rank purely through coupons saved and spent during such events. It just takes a longer time, patience is key.

A digression on topic but... Yukirin?

Goodness! Mabui so early? Very tempted... *gear cogs in head working...*
One piece of the puzzle in place for when the Kage treasures roll around.

Pains in the Sage Treasure and 30% discount for ninja frags is certainly very good news.
(*oh and... old Team B Oshi here haha...*)

This post was last edited by Durs at 2016-11-24 17:34

I believe Mabui is a regular rare in the Kage so it depends entirely on your RNG luck when you roll to the pay-gates as there's a large roster of rares in the Kage treasures.

Uhhh.. remnants of the last few events... was hoping for Shurado sigh.