Every flippin year I suggest Colin Hay but at least he got a cameo (Land Down Under) in the Australian Pink Floyd intro video to WYWH. Hugely underrated solo artist, great voice and pretty good with a tale or two. Can someone please take the hint this year.
There's been a Madness shaped hole in the lineup for a couple of years too. As the festival has diversified over the years, got bigger artists and still kept its feel they seem like a good choice for a spot of fun. I like the idea of Paul Weller too.
David Byrne would tick a lot of crossover / diverse-taste boxes as would Chris Rea and Mark Knopfler
Oysterband thoroughly deserve to be back, there's a lot of affection for that band and I'd hope it would go some way to make up for the apparent demise of the Big Session (I hope someone corrects me).
Under the heading of returning heroes, RT, Steve Winwood,
Plant and Krauss
For those suggesting the various Lakemans, Kathryn Roberts, Kate Rusby et al, can I make a suggestion we persuade / demand Equation reform as a one-off especially as Seth didn't make it when they did appear.
My usual perennial favourites of the 3 Daft Monkeys, Dreadzone, Treacherous Orchestra, Ellen and the Escapades, Urusen. I've not heard Shogglenifty live so I'd suggest them too. (EDIT, how funny someone else for the Shoogs as I was composing this)
Mike Harding as compere for at least one stint.
Any number of smaller bands that deserve a bigger audience, Green Diesel for one as they're fresh in my mind.
And ladies and gentlemen, out of left-field, I bring you... Sparks
As for fantasy artists, I'd love one of the hugely big names to secretly guest, do a couple and disappear leaving us all gob-smacked. I hear Kate's back on the road, she might get a taste for it.
Yours hopefully....