Indeed. Wild tigers (and their prey) in Russia have declined again during the last 4-5 years (although they may have now stabilized during the last year).
source: WCS Amur tiger monitoring report 2010, link:
The Amur Tiger: Scientific Publications
The population has been beset by poaching (none have bred outside protected areas) and, of lately, disease - possibly caught from domestic dogs they take as prey. To sum up, they are very vulnerable.
On the plus side, the Chinese are attempting to protect a large area on their side of the Amur river, and have clamped down on poaching. Now it will take a while for the prey base to recover, but the Chinese side has the potential to become quite good tiger habitat (winters are less severe than in Russia, and the native sika deer can reach high densities).
So although translocation of wild tigers is the most feasible solution, it does harm the wild population in the Russian Far East. More than a thousand Siberian tigers exist in zoos, and their gene pool is actually much more diverse than the wild Amur tiger stock.
But this is a difficult proposition; very rarely have captive large predators been successfully "re-wilded". Two such programs exist now, one for the Iberian lynx, the other for the Amur leopard.
To sum up, I wholeheartedly support this project. I think it is a great idea, and it might help restore at least a part of the tiger's lost range and numbers - but it will take time (to build up the prey base in Kazakhstan), good protection, good science, experienced personnel, and careful consideration (wild or captive stock?). The good will is there, and this may be a beginning of something great.