Unless you are willing to spend good amount of $$$, then there is little advantage anymore to level freezing.

1) There are easier ways to get adv refine runes now (and in much higher quantities).

2) There is little net sun coin gain from level freezing. You can get ~1000 more sun coins from top 3 in SWB (you will have to be an active killing machine which means $$$), and ~100 more sun coins from matsuri (the last 2 wins only give 100). over a week this is ~3200 sun coins. But, you give up sun coins from cat quiz, jin rescue, and 9tails rescue, which is about 2400 sun coins (3000 if you can get top 3 in 9tails). This puts your advantage in sun coins to ~200 sun coins. Getting sun coins used to be a hard thing to do for f2p at a high level, but with ninja outburst and arena matsuri, it is very easy now to max out your sun coins.

3) There is little advantage in Matsuri, as the pool of players you face around your level is very small. You will mostly be fighting 90-105 level players anyway after 1 win (and sometimes before).

There are really only 3 good reasons to level freeze now.

1) Time, you can skip events, which means less time needed to put into the game every day. And not playing for a couple days won't be as big an impact on your standing.

2) Struggles with beating Strong Approaching/Matsuri. If you have raced up in level too fast (say level 80-85 and power <50k), then you might want to level freeze for a little while to strengthen up a bit.

3) You have already been level freezing and you are a 200k power player whose favorite part of the game is dominating SWB.