Yes, Medicare and Medicaid reform are politically too difficult to achieve, because the people who receive the handouts of Medicare and Medicaid are too large of a voting block for any politicians to want to take it on. Any politician that votes to reduce Medicare and Medicaid knows that they are committing career suicide.
It might be possible to reform Medicaid, even though that is going to cause some people to decry the oppression of the poor. But Medicare has to do with older people, and we are fast becoming a huge voting block and also people that the young folks do not want to seem to be harming, especially since we're all getting older!
The reformation of Medicare and Medicaid is difficult to achieve in that it requires the reformation of the entire healthcare system and healthcare insurance industries, which is a very large task. Aside from having to reform the entire industry, people will not agree on what parts to change and what to keep. Politically, representatives may not be able to take a direct stand because the task is so large and includes other policies that would be affected by Medicare and Medicaid reform.
While both the Democrats and Republicans have very different ideas on how these programs should be funded and run I think that both sides recognize that serious reforms need to be put in place to make sure these programs are sustainable long term, I think eventually you will start to see small reforms turn into larger reforms.
Considering they are already great programs that have paid dividends over the decades and are, in general, run very smoothly, I don't think reform would be a large burden. The reason being is that much reform is not needed. You just need to do a little tinkering, and the job would be done.