There's really not much to say aside from the fact that with an 80 seconds cooldown at level 20 Morrigan ult can be used every 40~ seconds on average when using a 40CDR build with 4-5 ticks of Chrono's Pendant passive and at least 1 tick of Spear of Desolation passive. So the one simple question I have for the design team..
Where is the counter-play to this, if not in the early game?
I feel like changing the ult to a 120 seconds cooldown at all ranks would be far more acceptable, because in that specific scenario in late game with the aforementioned 40CDR build, it would raise the average cooldown of Morrigan ult to 65~ seconds.
To anyone who doesn't think it's that big of a deal I direct your attention to The Morrigan main who goes by the name of 'Yotsuyu'.
https://smite.guru/profile/7270092-Yotsuyu/champions
At the time I am making this post Yotsuyu has played The Morrigan in 5,388 matches with a total win rate of 75.97% and an average KDA of 4.24(Actual KD of 3.16). Additionally this player spends 63.4% of their matches in conquest(ranked & casual combined).