Is it advisable to change three trustees to one?

MJB - personally I do not like having co-trustees.  It is very inefficient.  I would select one child to manage the trust.  That child should be the one who has the skills to be a trustee.  If you're concerned about what the other children might think, you can put in safeguards to prevent the trustee from running amok.  Example, require signed approval from the other children before the trustee can sell assets of a certain dollar amount.  You can always divide the trust into 3 separate trusts and let each child be the trustee of their own trust, but you have to understand this might incur extra cost that could be avoided by having a single trust.