you said everything,tsunade doesn't have the speed,she's late and won't be able to dodge kamui.tsunade doesn't have the speed ,she's at kilometers of kakashi's speed .
-->she can't touch kakashi at close range and kakashi will predict all her moves with sharingan,he's too fast 4.5 vs 3.5 for tsunade's speed.
-->tsunade is only kage to heal and lead the village , she's reputed for her healing jutsus,not for her fighting skills,speed etc...
1 kamui at close rangewould be fatal for tsunade