While I agree with most of Chris's answer, I have a slightly different perspective:
The reason for the change is precisely because NY law is neutral (neither A nor B), not to mention well-known and well-respected. As a result, the choice-of-law issue disappears - neither party wins, and neither loses on this negotiation point. In other words, the other party is removing this issue in an effort to reach agreement.
Don't spend time or money worrying about unintended side effects / liabilities - you probably cannot readily determine whether they exist or what they are at this time, or which party they would favor, and they probably are not material, in any event.
The issue you didn't mention is whether there is a forum-selection clause - i.e., whether the parties agree to (perhaps exclusive) jurisdiction and venue in A or B. That's the provision that gives one party a noticeable tactical advantage if litigation occurs.
Disclaimer: This information does not constitute legal advice and does not establish an attorney-client relationship.