Well, depending on your perspective, not much worse than the implications of using a different web browser. If you're concerned about adding web browsers to your primary OS install, you could use a virtual machine for browsing the web. Maybe even a virtual machine for each particular web browser.
You have to consider that Google is already tracking everything you are doing with their service, to at least your public IP level. Logging into a Google account gives algorithms that are already serving you information, slightly more fine grained control, from advertising and video suggestions, to search results. If there is only a single user for your public IP address, using an account isn't likely to change any of your algorithmically tailored results, but it will get rid of some of Google's nuisance prompts, give you a few more customizable settings, and save your progress when watching YouTube videos. If there are multiple users in your household, once you start using an account, searches made or videos watched on other accounts or from browsers that aren't logged in won't influence each other. When not logged in, your browser gets results at the finest level possible, which is likely your public IP address coupled with your browser User Agent string.
The fact that you're using Internet Explorer is part of the underlying condition here. Could Google restore the older behavior for Internet Explorer users? I'm sure they could, as it only seems to exist when you aren't logged in and using Internet Explorer, which leads me to believe it's intentional. Can the behavior be worked around? Yes, but it's not practical with Internet Explorer. The behavior is tailored to the User Agent string that all browser report to websites. Unfortunately, there's no way to create a completely custom User Agent string for IE11 outside of using the F12 developer tools within the browser, and those can't be saved, rendering them unusable for any sort of permanent fix as you need to make the change for every browsing session, which is far more work than just clicking inside the search bar.
Unfortunately, the only permanent solutions I see are to log in with a Google account, or to use a different web browser that does not exhibit the behavior.
This is a known issue for users of Internet Explorer that has been present for many years so I don't expect any sort of solution from either Microsoft or Google.