Well it depends on what issue you are talking about. If you're talking about healthcare, maybe, but does that mean you should just give up? should you really tailor your principles to what will immediately make it through or should you fight for things you truly believe in?

I'd also like to challenge the notion that many of his policies are "too radical" to make it through. Rather, I believe it is money in politics from special interests that will block many of his policies. For example, Sanders wants to implement a carbon tax. This is a great policy and if you ask any economist they would agree. However, it's not hard to imagine that it would be difficult to get this through congress. I don't think it's because the policy is too "radical" but because a number of members in congress publicly say climate change isn't real, a statement that is so ill-informed it's clear it comes out of special interest money flooding congress to keep climate mitigation policies from occurring. The same could be said for other policies with are not radical, such as universal background checks for gun purchases. Even though there is massive support in the U.S. for this policy, special interest from group like the NRA will keep it from sailing smoothly through congress.

On foreign policy, Clinton does have experience but she is very hawkish. She has been pro-military intervention at virtually every time it's come up. Sanders would not move to use military intervention, a policy which he does not need to get though congress. So I suppose if you are more inclined for the United States to get involved in war and intervention, Clinton would be a good choice. Otherwise I'd say Bernie is your man.

Also would like to point out that even if Clinton's policies are less "radical" than Bernie's, they still won't make it through congress. The Republicans have spent so much time, money, and effort smearing Clinton's name and whipping up an extremely negative image of her among their base. Clinton is so disliked among republicans that not a single republican senator will ever be able to agree with one of her policies, even if it makes sense, because now it would be political suicide. Bernie on the other hand has a high favorability rating among Democrats, independents, and even Republicans relatively. He has a history of working with Republicans to get things done, such as when we worked with John McCain to get comprehensive veterans benefits passed.

There is though one policy of Clinton that the republicans would agree with and probably pass. And that is her position on privacy. She is not very pro-privacy and wants to do away with encryption for citizens' personal devices and possibly place government back doors in all these devices. Not only does this lessen security for everyone (because now there is a known exploit) but it is a massive breach of our privacy as citizens. So with a Clinton presidency, you can expect just as much not to pass as Sanders except for policies that blatantly erode our right to privacy.