iam super tired right now so just some basic informations
yes warden can still heal just fine

in pve meaning astral and raids you wont have much of a problem to match up with a summy or cleric
but now we come to pvp... i see a serious problem there cuz of the mechanic of the warden heal :/ its strong yeah but you need to "reload" like a gun and thats where the problem lies cuz cleric and summy get new heals with time without doing anything (getting blood for reha as summy or getting fanatism for holy healing as cleric) as a warden you dont get anything passive thats why when they cc and focus you you are toast

not saying its entirely impossible cuz i already did it...but its pitful compared to a cleric or summy nowdays...
to the matter with your pet well you can and probably will send it on the enemy but its not really that important exept you want to use shred to gain static charge faster to reload instantly
wow so tired... more information is not avaiable 3 am ;D