1% would be a 10% reduction, and 2% would be a 20% reduction. Would these be catastrophic? Perhaps not, but when the current level of witness rewards were set (as part of a previous hard fork which already cut them by 80%), that was done with a goal of maintaining a safety margin in case of realistic but pessimistic scenarios on the Steem price and operational costs. 10% or 20% reduction would be a big hit to that safety margin.

Given:

1. Desire to maintain the core blockchain operations at a safe level
2. The poor performance of the content reward pool in numerous ways
3. The observation that SPS and content rewards do the same fundamental thing (both are proposals to be paid by stakeholders for contributing something of value to Steem) and should therefore be considered on the same "budget line" so to speak.
4. The reward pool already funds proposals of various sorts, developers, community projects, marketing, etc. not only "content creators". Post-fork these can shift to SPS which again means that the two pools ought to be viewed as shifting on the same "budget line" (projects using SPS instead also means leaving more for content creators, in rough terms offsetting the shift).

many witnesses and stakeholders, myself included, view the proposed split as the best tradeoff, despite what may seem like "unfairness" when viewed solely from the perspective of this group vs that group. Sometimes perceived "fairness" can and should take a back seat to function and good economics, particularly when you are talking about an arguably failing project which if it continues on its current trajectory is likely going to ultimately result in no one getting anything.

Finally, it may be a hard truth to hear, especially for community members and content creators such as yourself or @meesterboom who absolutely have contributed a lot, but the content reward pool by design is supposed to be an engine which drives Steem's growth, not only with literal "content" but by attracting and retaining a growing community of people who contribute meaningfully to Steem. Sure there are some who do this, but as an overall mechanism, it clearly hasn't worked and on that basis alone is a prime candidate for having a slice of its budget reallocated to better use (or at least different use with the potential for more value add).

Witnesses, by design, are supposed to securely and honestly sign blocks to maintain the integrity of the network, securely and honestly adjust blockchain parameters, and approve hard forks (which in practice includes some consultation with developers on what is included in hard fork proposals). That portion of the system has generally worked, including at low Steem prices, and most if not all of the current witnesses are doing these things well (this hasn't always been the case).

The bottom line is that witnesses are mostly (if not all) doing their job; the content reward pool has not been doing its job. Looking at this from the perspective of what is best for Steem as a whole, the reasons for the proposed adjustment to the budget ought to be pretty clear.

Different adjustments can be made in the future with the benefit of further experience.