Lots of cards in certain level they increase an stat or an ability and they reduce another stat, this is for ''balance'' , but this make the card worse in certain battles sometimes in most battles.
There are tanks that lose an HP point in certain levels to gain an attack or an offensive ability, yes an attack point is more value than others stats but for a tank you are making it worse for most matches even more when this tank have a shield ability or something else that make his HP a lot more value than 1 attack, Prismologist reduce his hp in level 4 to gain Forcefield you will put it on the back to cover for sneaks attacks and if you have level up her until 4 she will die sooner than if she was just at level 3 in most battles, there will be a few battles when you find Sand Worm and them finally your level up card is better than his previous level but there is not sand worm in a majority of battles.
There are some exceptions with the powerful abilities like Switfness or Strengthen, here the unit is not really losing an stat as it is increasing it with the ability, like Supply Runner: he reduce his life from 6 to 5 and gain strengthen so he end with 6 life anyway.
Main Problem: dis-encourage players to level up cards and this is bad for the market, why would you going to paid 20 $, 30$ or more to make more weak your card, of-course if you are planning to level up more than 1 level at the time it may end stronger but not everyone do that, not everyone are planning in maxed out the cards. We should not just ignore middle level of cards and think ''well just level up it more''.
Solution: If is really needed for balance star the level 1 with less one stat less or have certain level without any change like Renova from level 4 to 5.
Others ideas to help splinterlands I had recently:
Achievements with Rewards: They give a sense of progression in the game make you feel that you are going somewhere not just running in circles and can encourage renting, ownership, playing more(spend on energy) depending on the type: https://www.splintertalk.io/@caimanx/achievements-with-rewards-for-splinterlands
Give Riftwatchers packs on rewards chests: greatly increasing the value of Daily rewards while reducing the amount of rift packs encourage people to buy more: https://www.splintertalk.io/@caimanx/riftwatchers-packs-for-rewards-chests
Voucher-shop: We need something permanently or seasonal limited to spend our vouchers so they can rise, if vouchers rise, SPS will as well: https://www.splintertalk.io/@caimanx/voucher-shop