I agree with this, BotRK scales at least with attack speed, whereas Liandry's doesn't scale with anything, aside from its arbitrary synergy with Rylai's. Neither BotRK nor Liandry's are in a particularly great state right now, but at least BotRK's effects still feel better to use.
To be honest, I feel the whole anti-health and anti-resistance systems in itemization are kinda messed up at this point. The existence of anti-health items like Liandry's and BotRK means anyone can start ignoring a portion of the enemy's health, which forces either health items to give too much health in compensation, or those two items to be ineffective at their very niche, which is somewhat the case now. Similarly, armor/magic penetration means everyone gets to counter resistances to some degree, which inflates the values on armor and MR items. Basically, the very existence of items that counter existing counters to damage means that either tanky items need to give too many stats for tanks and fighters to survive, or those second-hand counter items need to be useless in order to not invalidate tanky champions.
In the end, I think don't think any mage should be completely shut down by health- or MR-stacking, and the only mages who get to really counter health are the ones designed for it, and should have the max health damage or pseudo-spellvamp to do so if they don't already. Basically, it would be better to have a League in which health, armor and MR could still counter damage, but never hard-counter it, and in which those stats weren't negated in large part by other items, which either give everyone access to tankbusting or end up being too weak to accomplish their goal, as is the case with Liandry's now.