Using the Noll-Scully measure of competitive balance under the trinomial distribution (since ties are a part of the MLS) I find that competitive balance is higher for the 2017 regular season than the average over the last 18 seasons. The average Noll-Scully has been fairly stable over the last five years. The Noll-Scully for the MLS 2017 regular season is 1.383 which is still more competitive than the other "major" US sports leagues. Here is the Noll Scully since the 2000 regular season.
Want to try to calculate it yourself? Here is my Noll-Scully competitive balance measure step-by-step guide. Note: I used the trinomial distribution.