I don't know what you mean by uzbeks have more mongol characteristics than kazakhs.
Are you sure you're not being confused?
3/4 is not exaggeration
Kazakhs
Altay
The Uzbeks look the least Mongol out of all all those Turkic I listed although the Uzbeks from the north including Northeast look much more like Mongol
ok here's why uzbeks are actually more mongolic than kazakhs. you see, both of these nations formed at the same periods. but their core tribes differ substantially. let's count them.
uzbeks are generally said to have 92 tribes. of these 92, there are 10-15 tribes that were populous and played significant role in Bukhara, Hiva and Khohand khanates. these tribes are Mangyt, Naiman, Kungrat, Kipchak, Kitay/Ktay, Saray, Keneges, Katagan, Kerey, Dulat, Jalair, Yuz, Ming, Uygur, Bürgüt. that's the very short list of most prominent Uzbek tribes. now of these tribes:
Mangyt: mongol tribe (were among the left wing of Genghis's mongol army. ruled Bukhara Khanate from 1750s to 1920)
Naiman: mongol tribe (were beaten by Genghis and afterwards scattered all over CA. almost every nation in modern CA have naiman tribe in them. even hazara of afghanistan have naiman clan).
Kungrat: were very prominent, high level mongol tribe (Genghis's Borjigin clan almost always got wives from this clan including Genghis himself)
Kipchak: Turkic, very well known tribe. no need for explanation.
Kitay: a.k.a. old-time Kitan people of mongol origin. were known from 3-4. centuries, founded several states themselves.
Saray: one of Kipchak sub-tribes. Turkic.
Keneges: mongol tribe, information is they arrived to CA with Jochi.
Katagan: mongol tribe, came to CA with Chagatai Khan.
Kerey: mongol tribe.
Dulat: Turkic.
Jalair: very well known mongol tribe. Modern Mongolia's mongol population stems from Jalairs of Gersene Jalair Han's 7 Halha. also, these guys founded Jalairid dynasty of iran.
Yuz, Ming, Uygur, Bürgüt: all Turkic.
these tribes of mongol origin were completely turkicized when they arrived in CA with Shaibani Han. they were culturally and linguistically turkics. and as a matter of fact, since they were all nomads and relied on pastures for their flocks of bovine and ovine animals they had to settle in the delta of Zeravshan and Amu-Derya rivers. In these conquered lands, Uzbeks formed two khanates, Hiva with center in Urgenc and Bukhara with capital at Bukhara. if you look at the map of uzbekistan, you'll see that narrow corridor in norheastern part. that part down to Termez in afghan border was the new home of these tribes. and that's why uzbeks from these parts look more mongol. in addition,those northern parts (esp. tashkent region) of uzbekistan were under kazakh rule and was home to mongol katagan tribe. and we also must note that uzbekistan as we know it now, comprises of tajiks, people of iranian origin and sart, who are viewed as turkicized people of iranian origin, who live in towns. sarts also call themselves uzbek, but you can easily spot them, for they have darker hairs, lighter skin and bigger eyes than your standart uzbek. and last, but not the least fact is that, during 17-19. centuries turkmen raiders often made raids into iran and brought many persian captives, whom later were sold as slaves. it's estimated that in 2 centuries more than 1 million persian slaves were sold this way. and think of demographic impact of this. and we must count interracial and inter-tribal marriages, because marriage of people within one tribe was forbidden, so they had to marry from other tribes (our ancestors knew of gene pool thing ahha
) and these slaves were generally occupied as secretaries and clercs. it was reverse of mameluks, turkic slaves who were bought to serve as soldiers and commanders in the armies of middle eastern muslim states.
P.S. karakalpaks comprise of kungrat, kitay-kipchak, keneges-mangyt and their sub-tribes. so, there shouldn't be any anthropological difference between them and uzbeks.
P.S. i was planning to write about kazakh's main tribes also, but i got bored ahha.