What we were told by the OT is that either left handed or right handed is fine, but ambidextrous is bad. An OT sees strong handedess of one sort or the other as important for neuro development / maturity. They also need a strong understanding of which is their left/right and should be dominant on the same side for hand, foot and eye.

I am sure my DD has dyslexia, though I am having trouble getting anyone to diagnose it now that she reads at/above grade level, despite her history and her IQ (MG). When she had her first OT assessment 2.5 years ago she had significant problems crossing the midline and she has mixed dominance. The OT said he could tell from her assessment that she was great at "where's Wally", but couldn't read - so some visual skills were way above average, others well below. She has a great sense of rhythm and rhyme. She spoke early but we now realize had some language quirks that weren't normal. But she has extremely poor phonemic awareness, even after (finally) learning every possible phonetic rule. She has CAPD and she had incredible trouble with mapping sounds and concepts to symbols.

Piano, swimming, Horse riding, OT, 1:1 reading instruction and time have made the world of difference to the left/right, crossing the midline and her reading.