I wouldn't want them taking away significant resources that could better be used making truly new content.
At the same time, it would be a brilliant move to have a 'classics' lineup of HD versions of the most popular current-gen games IF they found a way to very quickly port them over with higher framerate, AA, 1080p, etc. That could theoretically be done with very little time with the right tools. However, like I said, I wouldn't want them taking away dev time from the true next-gen games at all. It would have to be a project led by a specific team that didn't get pulled from a next-gen title.
Millions of Xbox 360 owners will switch to PS4, and they might have missed out on many PS3 classics during the current gen. Similarly, millions of PS3-only players may eventually pick up an Xbox One, and might have missed some stellar 360 exclusives. It would be nice for those people to be able to play those titles without having to buy an older console.
So my answer is a qualified 'yes', but not if it took away from other truly new projects. I personally wouldn't re-buy anything I already played through, but for titles I missed, I wouldn't mind at all buying a re-release with improved graphics and decreased load times on the new hardware. It would be important that these titles also be priced at $29.99 MAX, and more like $19.99/$24.99 for most of them. After all, all of the art, music, game design, direction, etc, etc was already done and paid for already, and if the game was popular enough to be re-released, it obviously was successful and profitable. Given that simply porting an existing title doesn't take a ton of time/expense, it would be insulting to see it priced at $49+.