Yes. And no, as it is much easier to cap (or better, tax) the excess money than to try to prevent the money from doing what it shouldn't. It's better to tackle the problem by the root.
But if there was a method to reclaim democracy without a cap or excess wealth tax, that is easier to implement the taxes, then I'd go for that.
Certainly a fair and appropriate tax system should be in place, whatever that may entail. The idea of caps seems much more problematic to me. What arbitrary number marks the line of having "too much". How does the cap address differences in the cost of living across regions in the same country or even the same state or region within a country. If the same amount of money gets you a McMansion, swimming pool, and golf club membership outside of a major metropolitan area, yet only affords you a small apartment or a WWII era bungalow within a major metropolitan area, how is it fair if the national cap prevents anyone from owning either?
Perhaps you will respond by saying the cap would naturally be higher, that it would be high enough to allow ownership of at least one residence in the most expensive areas, but that means there are still people with a lot more money than other people, and if money equates to influence in the political process, then that unfair advantage will still exist yet you've thrown a wrench in the existing system, affecting the flow of capital and market pricing.
I still think it would be better to focus on reducing or eliminating the relationship between money and political influence or power, as well as eliminating policies that unfairly shelter or enhance the advantages inherent in wealth building for those with assets beyond a certain level. No cap on wealth, but no shelter of wealth from appropriate taxation over a certain level. I would also favor tax free savings with no limits or strings attached for folks under some level of net worth as a means of encouraging saving and wealth building within the middle and lower economic classes.