In 2.0 arena was simply impossible without owning initiative AND a meta team with a barrier ninja due to the mechanics it had implemented at the time (you could meet only people withing a 3 points range from you and to begin to get +2s you needed to be on a streak of 3 consecutive wins).

In 3.0 arena became easier for f2p because the rules where changed to the current ones (you can meet anybody within your rank and every 30 more seconds of waiting time increase the rsnge of the ranks you can meet + the +2 appeared after a streak of 2 consecutive wins) and both han roshi sailor sakura and ay3rd samui darui meta could withstand most of the arena commonly used by spenders teams.

The current arena is basically: run shisui itachi anbu madara/maskedman/kushina habanero teams if you are f2p and retreat every time you meet a madara 5th kage summit team or a kisame samehada + agk/kurama team.