I think when investment is concerned, there is a need of finding deep knowledge of the proposed cryptocurrencies that can play as alternatives for bitcoin.
On your post, I got confused somehow, but I finally got what you are meaning. On my view I think ripple has advantages and disadvantages as you have just said but the investment decision matters.

I think people are not more concerned whether ripple is decentralised or not or it plays as a middle part, the most interesting is to find if ripple if reliable and profitable.

Moreover, if it is centralised then that is a big mistake ever due to banks and human beings manipulation, but would prefer it to be decentralised so as to prevent all the possible financial risks in the transaction market.

My view .

Thanks and happy new year