All the additional counterspell summaries you came up with

My post splintered into about a dozen different versions, so I’ll collect all the wonderful things that were added to it in one convenient place. If I forgot or misattributed any, or if you come up with some more, let me know!

Perplex: “What do you like more, your spell or your brain?” (tokenmancy)

Remand: “BZZT! Try again!” (tokenmancy)

                “…Not now.” (stormstouthideout)

Mystic Snake: “Sssssstop that!” (sarkhan-volkswagen)

Counterflux: “All your opinions are invalid! All of them!” (northernweird)

Draining Whelk: “OM NOM NOM NO!” (fresh-prince-of-beleren)

Flusterstorm: “Are you quite finished? Good. No.” (ty-based-keranos)

Voidslime: “Three flavors of fuck you.” (nerdcute)

Dream Fracture: “Haha tempo bitches” (thepeppermintpig)

Absorb: “I can taste the mana!” (missedtrigger)

Arcane Denial: “I hope you remember your draw triggers after your ten minute turn! Hahaha.” (missedtrigger)

Forbid: “I told you NO!” (missedtrigger)

Glen Elendra Archmage: “No so hard I am going to kill myself to stop it and then come back to do it again.” (missedtrigger)

Counterbore: No, and don’t think about trying that again. (ancient-chaos)

Guttural Response: YEEEEEEEEEEEEEEEEEES! (ancient-chaos)

Spell Crumple: “Maybe later.” (kinggeff)

Swan Song: “HONK” (masterofsporks)

     A couple were added to the original post, I think orzhov-fun-police added them but I’m not entirely sure:

Mental Misstep: “Even Wizards says no.”

Delay: “Maybe later.”

Forbid: “Nothing ever again.”

Mana Tithe: “Bet you weren’t expecting ME to say no!”

The design of Jeskai is a great way of showing the goals of a tempo deck. While tempo decks are definitely about doing things liking bouncing creatures to force your opponent to pay for their spells twice and advancing your board at the same time, they’re just as much about synergy. Getting the most out of your spells.

For example, look at Gitaxian Probe in Vintage. If you show a new player Gitaxian Probe out of context, they likely won’t appreciate it. Part of that’s not yet knowing the value of a free spell or the way cantrips can dig through your deck. But it’s just as much not realizing that Gitaxian Probe isn’t just drawing a card and letting you look at your opponent’s hand. It’s transforming your Delver of Secrets. It’s getting you 1/1s off Young Pyromancer. It’s adding 1 mana to your Treasure Cruise or maybe 1 to your storm count for Flusterstorm. You can pitch it to Force of Will.

Jeskai creatures work the same way. In any format they’re in, they grant these additional abilities to all your spells. Prowess is the most straightforward example and it’s relevant in formats from Limited to Vintage. Making your creature bigger just for doing something you wanted to do anyway is great for a tempo deck, particularly since their creatures might be smaller initially. We’ve seen similar “whenever you cast a noncreature spell” abilities on Jeskai cards in every set in Khans block. Whether it’s Mistfire Adept in Limited, Jeskai Ascendancy in Modern (for a time), or Monastery Mentor in Legacy and Vintage, that sort of effect is almost inherently powerful. The effect can be minimal, but the fact that you’re getting it frequently for no additional cost makes it great.

With that in mind, Ojutai Exemplars looks great. The body is solid and, as mentioned before, tempo decks’ creatures often start smaller than creatures you’d see in other archetypes, so starting off with a 4/4 for four is significant. 

But then it gives you a trio of other abilities just for casting spells. Unlike other useful pseudo-prowess abilties, Ojutai Exemplars gives you options beyond when to get the effect. Tapping a creature is basically two modes as is. You can tap down creatures to survive or attackers to deal the last bit of damage. Either can be useful when racing your opponent. Furthermore, you can win combat out of nowhere by getting first strike. In the same mode, you get lifelink to help you win races or get further ahead when your opponent isn’t doing anything. Finally, you can flicker the Exemplars to evade targeted removal. There’s an actual Morphling variant in this set, but with these kinds of abilities, Ojutai Exemplars may actually be closer to Morphling (the lack of a P/T changing ability is notable, but there’s no denying the versatility).

I expect to see this do great work in Limited and Standard. Keeping around this one specific creature isn’t as vital in other formats, so I think you’re more likely to continue to see cards like Monastery Mentor and Young Pyromancer in other formats, which provide similar (and frequently just better) rewards for cheaper.