My suggestion was two-fold : my last post was just addressing the second part : fame gain/loss in battle and how it can better reflect the relative strengths of the combatants.
The first part was directed more at what you suggest is the problem : that is to make fame gain more reliant on actions taken that strengthen a player : so, trading, building ships and banks, etc, would all add fame relative to the value of the action : a good example being CJ's suggestion of a 174k fame gain for building a SotL. Building or upgrading a bank should also build fame in a similar manner. I agree cashing in party stocks should attract the same gain as directly selling those stocks into a port would.
This kind of fame gain would be hard to shift without recourse to lots of voodoo, and the expense in turns required : or it would require a significant number of battles to be lost. There-in the second part : 'battle fame' : currently, you can pretty much calculate how many battles you need to lose to get under the bar : My suggested system is much less predictable as much will depend on exactly how your foe attacks you. To maximise target fame loss would mean closely matching the targets fleet strength. Downside is, your attacking fleet becomes vulnerable itself to counter-attacks from others. Make it more powerful to resist those, and then you lose the ability to influence the targets fame loss. A nice conundrum to solve, no?
Where difficulty will arise is that 'legacy' players have already avoided much of what fame would be gained from building up an account : My war-fleets have already been built, any fame from those builds will never be added to my total should a new method of calculation be implemented. But hide-out builds will add significant amounts of fame : if we use the same metric as the '175k per sotl', then a goldsmith level one will add 3.6mil fame just on the gold spent.
So, there would be your conundrum for any large player trying to minimise their fame to avoid combat : keep your fleets but no hide-outs for you : or build the hideouts and banks and smiths, but lose the 'low-fame' protection potential.