Well, some may disagree but it was schedulled to happen sooner or later... And actually, it's one of the best things they could have done. Vegas is their third home (after Laval, QC and Jupiter Island, FL). She doesn't have a to busy schedule, she has plenty of time to take care of her kids and do the things to loves the most... Being a mother for her children... While enjoying being a mother she can enjoy singing in a special made venue with a lovely, personal, show... Rene is getting older, her mom is getting older, Rene-Charles is growing up, her twins need attention and she's getting older too... I've said it once and I'll say it again... She has done anything she likes, she reached the top, she sold millions of records, she changed Vegas, etc... She is probably a billionaire when you combine their assets... She doesn't need to prove anything anymore... She has reached a turning point in her life and she has made some choices about it... Some may forget that travelling arround the globe, even in a private jet, is taking a toll on the person in question. It's very demanding... Changing of timezone's, lake of decent sleep, changes in temperatures, humidity, airconditioning systems, the flying itself... You can't underestimate what this all does with a human body... Just try it for once and go fly arround for a couple of weeks. Spend those airmiles on a round the world ticket and fly arround the globe in a couple of weeks time and you'll notice -soon- that it's not all glitter and glamour, even when flying business or first... And it's not all about her anymore, her children, but more important her husband and her mom who are getting both to a not so young age anymore. They don't recuperate so easy anymore and you can't rule out that sooner or later their health will go down... So the best thing she could do for her and more importantly her family is to settle down... And by setteling down in Vegas she gives everyone a chance to see her perform since you can be certain that she's still there in a couple of years of time. So everyone can save to see her since there's absolutely no rush...
Honestely? I -think- that 5 years could just be the beginning... I expect her to add additional years to the contract in the future. It will all depend on the health of her and her family in the first place and how the shows perform... Maybe there is a slight chance that she goes on a limited world tour again in about 5 years but I expect that we won't see something again like the Taking Chances tour... Those days are over I guess...
Will it ruin her career? No it wont... Celine has reached the top, she's standing there together with Madonna, U2, The Beatles, Elvis, Michael Jackson, Abba, Queen, Frank Sinatra, and many many more... The sky is the limit, well that's where she is right now... At the sky and thus also the limit...
Just my 2 (euro)cents
...