Changing fluid allocation will not solve the problem, since it is a corrosion issue and not a fouling one (dirty fluid/low velocity, for example). Furthermore, if you keep the existing heat exchanger geometry, you will encounter much higher pressure drop on the tubeside, causing lower operating pressure in the O/H receiver (if you want to keep flash zone pressore unchanged, that also means higher heat load of the downstream fin-fans = more flaring), or if you want to keep the O/H receiver pressure constant, it will result in loosing distillates into atmospheric residue, as a consequence of higher flash zone operating pressure. Maximum allowable pressure drop of the overhead vapors will define appropriate heat exchanger design - it is quite expectable to face inadequate heat exchange area when shifting fluid allocation and staying within allowable pressure drop limits - so this proposal will also have its economic drawbacks (i.e., a completely new heat exchangers).
Proper crude oil desalting process is 90% of battling corrosion problems in the overhead system. Make sure that your desalter runs with minimum 80% efficiency (if single stage) or 97-99% efficiency (two-stage). Ensure the absolute control of chemical dozing (neutralizer, corrosion inhibitor) and check overhead pH more frequently, 2-4 times per shift at least. Your problem in the heat exchangers is "first droplet condensation issue", and is originating from high HCL content of the column overhead vapors. Changing heat exchanger fluid allocation and/or design will simply not solve the problem.
