This is likely going to be the main flaw in the new patch cycle model. Designers tend to think across a span of time of weeks or months, as that's the time it usually takes to work on a feature, but players tend to think in the much shorter term, because what's most important to them is that their next match is fun. As such, while the big patch/small patch model may be productive, it's likely going to create a severe amount of frustration during the smaller patches, where players expect large amounts of work to happen and see comparatively little done in practice.
Personally, I think the idea of alternating between patch types is a sound one, but I don't really think size should be the concern. Rather, I think it would likely be better to have one patch focus exclusively on design, i.e. updating certain kits and items to change some amount of gameplay, or releasing a new feature altogether, and the next focus exclusively on balance, i.e. stabilizing everything and making sure the disruption from previous patches is kept under control, in addition to just addressing current meta-warping problems such as overperforming champions, unbalanced items, etc. Ideally, these balance patches should aim to provide immediate relief, whereas the design patches focus on more long-term goals, so that players expecting a balance issue to be fixed should not have to wait more than one patch cycle for that to happen.