Your central point regarding "a move to amortize goodwill would severely reduce the informational value to current and future investors" is misplaced in my opinion. Trying to force the balance sheet to reflect market values of business through adjustments to goodwill (and other intangibles) is too much and actually this is what detracts from usefulness in valuation.

Amortization and impairments of goodwill (and intangibles in general) are both non-cash adjustments that have no impact on the cash-generating value of a business which drives value. Best to ignore the whole exercise.

If one is evaluating an investment against purchase basis, then include ALL of the intangibles and goodwill without any adjustments - this is the cash investment basis on which one need to earn an appropriate cash return.

If one is evaluating the basic competitiveness of a business, eliminate all of the goodwill and intangibles (and back out any amortization and impairments) and view on a 'tangible only' basis as this is closer to the true cash 'earning power' of the business relative to comparable enterprises that may have organically grown their operations so that the 'intangibles' are embedded in the margins and overhead efficiencies.

In neither case is the value of the business based on such 'accounting adjustments'. [An entire separate response could be based on critiquing the quality of the impairment opinions frequently sought from audit consulting practices and the 'games' companies play in the timing and magnitude of such impairments.]

While there may be special situations where it is necessary or possibly useful to value a particular patent, brand, or 'whatever' intangibles, say if being sold separately, this is truly the exception, comparable to breaking out and selling an operating division, and would encompass all the 'dirty' assumptions that are then required to disentangle from the overall enterprise.

In short, reported accounting numbers are better with less adjustments than more and the potential for distortions in goodwill impairment testing is greater than any transitory confirmation of a negative result [here I note in ending that the Kraft-Heinz example of the impairment on overpaying that the share price had been declining sharply for some time before the impairment announcement - markets do not wait for accounting - and the further fall might have had less to do with the accounting than the loss of confidence that management could turn things around.]