It would be brave to kill him off, but currently utterly useless. There is nobody that has the hard man image he portrays so well, albeit old and dying. They tried bringing Vincent in as the hard man, and it just didn't work, Ben has his angry outbursts but doesn't compare mentally or physically, they even tried it with Mick, but all he can manage is an evil look and some rhyming slang.
Perhaps I'm just wanting the show to be back at its best as was seen IMO during the 2000s, Phil financially well off and owning 'the square' along with his rivalry mainly with Ian, but also with Steve. Ian with his businesses, eventually being overstretched and him going bankrupt, the rivalry with Steve over many things - women/money/etc.
That just isn't being fulfilled right now, and whilst he isn't exactly in fighting fitness as he was then, and the same goes for Ian, they are both at least a link to that past that just has no replacement just yet.