The history store cursor has two additional functions, namely:

• 
  __wt_curhs_search_near_before
• __wt_curhs_search_near_after

These functions and the associated internal functions are additional code that requires maintenance. The bounded cursor work which completed some time ago should be able to handle these nicely.

Now I haven't yet done a full investigation on feasibility, or on other places a bounded cursory may help but I think this is certainly worth the investigation.