Converting to Echosign form will help, as it gives you access to echosign form fields in Acrobat 11.
In any case though, it's enough to make the fields read-only in Acrobat. Echosign will honour the Acrobat read only flag so no need to do that again in EchoSign.
But yes in the echOsign form editor you can only set this one by one currently.
In your scenario the plament of fields is never editable by a signer. Filling a form obviously is.
Readonly is one way to deal with that,
the other would be to convert to echosign form, then to assign the field to either a prefill or sender role. This basically also makes the field readony for the signer.