Yes, and every post you've made this week has been about Darius, so we know who you play. Here, have some facts.
You've created ideal circumstances for your own argument in a vaccuum that ignores how Riven works in game. IE, Riven doesn't rush Ionians, she builds them after she has a damage item besides her brutalizer.
By level six if she's bought a Brutalizer and CDR boots thats 2337 gold spent on 25 damage and 10 armour pen, but hey, 25% CDR, which /if/ she has 5% CDR in runes (because who needs magic resist?) and she definitely should have the 5% mastery, is 35%, not 30%.
Then, okay, sure, her cool down is a bit over a minute. But she does no damage and it doesn't matter. That's also more gold than she should have by level 6 unless you're playing wrong against her.
The long and short of this is that even with 5% in runes that's 20% cdr with the brutalizer at 6, IE, the lowest CD she can realistically have it in laning phase, is 88 seconds with 20% CDR after, you know, investing in CDR.
That's still a significant cool down, and her ult still isn't a point and click AD scaling true damage nuke that gets stronger with stacks of AD scaling magic damage.
Edit: And why don't you have teleport in your example?