Don't get me wrong. We LOVE Regent and we'll be cruising again on the Voyager in May, with another Regent cruise booked next June. But for a first time all inclusive Med cruise with really exceptional excursions you might look into Tauck's Small Ship cruises which they run on Ponant ships. Tauck is renowned for their extraordinary land tours and they've translated that into a group of great ocean cruises. I'd strongly encourage you to check them out.
Regent's ships are much more luxurious than the smaller Ponant/Tauck ships. The Ponant cabins are more sparse (Nordic, I guess) and there are less dining options. (Although Ponant is a French cruise company so the food is pretty great for a cruise ship.) Like Regent all drinks and tips are included, so that's apples vs. apples.
But the point of these Tauck/Ponant cruises is NOT on the boat. It is ports, the expert and exceptionally engaged Tauck tour directors (several for each cruise), the guest lecturers they bring onboard and the very special excursions. Excursion groups tend to be much smaller than Regent groups. Never over 30 people and sometimes just two or three of us with one of the expert tour directors taking us to see something really special they've personally discovered in that port on a past trip.
So many Regent passengers seem to schedule their own excursions, even though they've already paid for the included ones because they aren't satisfied with the provided offerings. For the most part, in my opinion, at least, the Tauck excursions, are the sort of tours you remember for a life time and you hope for when you schedule your own private guide. Many are things you can't even do on your own, like a private before hours tour of The Hermitage, with a demo and lecture by the man who winds the gold peacock automaton.
If I could put the port and lecture experience of the Tauck cruises with the gorgeous ship experience of Regent I'd have the absolute perfect cruise package for me.
If you do go the Tauck way I would suggest finding a Tauck group only cruise since some are run along with regular French passengers booked by Ponant and that can be a bit distracting.
Any way you go I know you'll find the right cruise for you and have the time of your life!