I think that "We would like big markets." can be accepted. I understand that omba means request/ask for, it has cognates in the many Bantu languages I encounter, but the translation ''would like'' seems more suitable in this case. It makes more sense to an English ear. Translation is more than just word-for-word.
Soko comes from Arabic سُوق (sūq, "market, souq, bazaar, street of shops"), from Aramaic שוקא or ܫܘܩܐ (šūqā’, “street, market”), from Akkadian sūqu (“street”), from sāqu (“narrow”). Compare Hebrew שׁוּק (shuk, "market in the broad sense; a street market"). Spanish zoco ("market") and English souq ("street market") come from the same Arabic root.
these look good, you should try to add your extended etymologies back to Wiktionary.
Some explanation about tunaomba vs tunataka would be helpful. I guess: -omba = wish for -taka = demand. ??
Tunataka is more of the statement that "We want" while Tunaomba is a question. Omba can also be used for (probably not ritual) praying
Kuomba can be used for ritual praying. Usually in the form "kuomba mungu", as in "to ask for from God".
Tunaomba is "we ask for" or "we request" and is considered fairly polite. Tunataka is "we want" and is somewhat polite (tuletee or tupe--"bring us" or "give us"--are much less polite).