Dear Kwan,
I stayed in The Netherlands (often erroneously called Holland) for four years when I was growing up. So Europe is like a second home to me, and I'm as comfortable in The Netherlands as I am in Belgium, Germany, Austria, Switzerland, Luxembourg, France, northern Italy, and yes, Liechtenstein.
More recently, we've been to France three times in the last three years. This year, it will be four out of four.
Some things for you to consider:
(1) First time does not mean you have to stick to only cities. You can check out the lesser known towns which often have their own charm, have far less tourists, and are much less crowded. If you love scenery, you have to check out the Swiss countryside or Austrian countryside. You won't find that in any of the cities or towns.
(2) Paris ... yeah, but it's also a great place. You should spend a minimum of four days there exploring both the touristy as well as the non-touristy areas. Walk around randomly.
(3) Those four places in Switzerland will take you at least 1.5 weeks.
(4) Munich: it's in between Luzern and Vienna? Not according to my map. Just skip it.
(5) Vienna: It is so very out of the way. You should leave it to your next Europe trip.
(6) Italy: how many days is your Contiki tour? Rome is nice, but beware the pickpockets and snatch thieves, as in any large city.
See, I've managed to cut it down to three countries already for you. I think it's much more manageable and your holiday will be much more enjoyable too.
Also what is your budget like per person? Seems like you would be spending quite a lot of money, given your current itinerary.