Can I replace my wye-delta controller with a soft starter solution?

Yes. You can use soft starters for wye delta motor starting. Please click on the link below for further information on replacing a wye-delta or star delta starter with a soft starter. 

http://www.eaton.com/ecm/idcplg?IdcService=GET_FILE&allowInterrupt=1&RevisionSelectionMethod=LatestReleased&noSaveAs=0&Rendition=Primary&dDocName=AP03902009E