Been fighting for a while now in the PVP part of the game, and I seem to run into the same problem.
I normally hang about 4500-4600. Each time I close in on 4750 I am suddenly go from people all about my level with similar dinos, to suddenly facing down people with dinos whose level is at the lowest is one to two above me if not higher, with full high rarity teams.
Then there are times when I get hit by a streak of loses where I could spend over 30 minutes trying and failing to win. Some from bad teams matches, others to level. Which not only is very frustrating, but the reason for one of my friends to leave the game.
I think it would be wise if the ranking was spread out more. It is one thing to face someone who has a dino whose level is one or two level above your own on a semi regular bases. It is entirely something else, to face down 5 plus people whose ranking you should not even somehow be in.
Though I do have to laugh at one fact, somehow I with the lower powered creatures, and no where near getting anything above a legendary, can take on those levels above me at times.