Flash isn't dying, but I agree the game could use a rewrite. You can't seriously think this game is well made from a technical perspective. Now whether this is a problem is subjective and like Jenkar said, it is what it is. Personally I can live with its faults as long as I avoid pvp and enjoy the game as a casual thing akin to Bejeweled or something, but in its current form there's no way I'd consider playing it competitively.
There's a large community of elements players who disagree and think the game is great. That doesn't mean there is not scope to improve it, but generalised comments like this are simply not helpful. If you can identify specific problems or, even better, solutions to those problems, then you have something worth saying. Otherwise, bland generalisations are no better than hot air.
On the subject of Flash. There are signs that adobe will cease to support the platform over time. Whether an open-source project will fill that void or whether an alternative platform will emerge supreme remains to be seen. For the moment, flash is a reasonable choice of platform and given the large amount of developer time that has been dedicated to it already for elements there's certainly no rush to change. If elements is still to be around in 5 to 10 years, however, a change of platform might need to be considered if the demise of flash really transpires. If that is the case, then offers of help to transport elements to a new platform will be much more useful and interesting than simple 'I wouldn't have done it on flash' type comments.