Huh? If curses don't have any negative effects, then why does getting cursed by Strahd on the stairs kill so many people? Why is there a "Remove Curse" potion? Where are you getting this information from? Reading this,
https://www.enworld.org/threads/how-do-curses-work-in-d-d-5e.681858/ makes me think curses in D&D go way beyond simply slow movement. Although the cards are supposed to give benefits, they don't always do that. A +1 pact bonus isn't going to help a paladin at all. They are called curses, in my opinion, because sometimes you are going to get ones you do not want or that do not benefit you in any way. Now, if you are complaining that the remove curse cards should be for sale in the DDO Store, then I might understand. This would work the same way pumpkin heads can be removed by those who do not want them. They have given people the ability to remove the affect by pressing shift. If you don't want it to be your block key, then you can adjust your UI however you want it. (For example, I hit with my "J" key.)
Further, I cannot find anywhere that says feather fall does anything EXCEPT stop you from falling quickly.
https://ddowiki.com/page/Feather_Fall Since it can only be cast when you are falling and the spell ends the second you land in PnP, I find it hard to believe the DMs here would make it do anything other than prevent you from taking damage from a fall. I am melee, and I wear feather fall from the moment I can put it on after reincarnating or creating a new character. I do, however, occasionally, remove it inadvertently by removing the item. I never know the difference until I am falling. And I fall a lot. I jump off in Sharn and Gianthold, for example, when I am running to quests. I can't imagine Tempest Spine without it--even if you survived getting thrown off, you would then have to run back. I certainly don't want to think about toggling it on or off.
Please enlighten me on where you are getting these stats that say it slows down your attacks. Simply "feeling" like you are moving slower is not a good way to judge things. For example, right now, I feel like I am sitting at my computer stationary. However, in reality I am spinning around the world at the rate of 1000 miles per hour and spinning around the sun at the rate of 67,000 miles per hour.