I think what one should bear in mind is why the Buddha used this exact term to refer to five constituents of a being. In theory, one can use literally any word as a term having literally any meaning. However, in practice one often chooses a specific word as a term because of the two major factors: denotation of a word reinforcing its metaphorical significance and connotations of a word facilitating its reception.
Let us just set aside the possibilty that khandha as a technical term in philosophical discourse pre-dates Buddhism and consider why the Buddha could single out the word.
Denotation and Metaphor
In its original Vedic use, still found in compounds in Pali texts, the word ‘skandha’ meant ‘tree trunk’ or ‘upper torso’. Honestly, I personally don’t see how a word denoting something quite solid and perceptionally unified as torso or trunk could come to mean something composite like ‘heap’ or ‘bundle’. Even if you look at the word Gombrich discusses in ‘What the Buddha Thought’, aggi-khandha ‘blazing fire’, it’s hard to think of the flame as composite, ‘trunk of the fire’ just doesn’t sound like something inherently composite. If we translate and think of khandhas as ‘heaps’, ‘bundles’ or aggregates, it means the linguistic metaphor gets broken down somewhere along the way. Finally, it is somewhat unclear why the Buddha didn’t use the word like ‘bhaṇḍikā’, then, a word clearly conveying an image of something divided into parts, something composite.
What could be an alternative explanation? To start out, I don’t claim this is the only true interpretation, I don’t even claim it is true at all: there is a dire lack of evidence on my part to make such claims. Anyway, I think it could be interesting avenue of research. Let’s consider a specific type of metaphor that comes up in Russian and, quite possibly, in other European languages. Here’s a quote from the Soviet mini-series Meeting Place Cannot Be Changed:
If there is Devil in the world, he is not a goat-legged horn-bearer but rather a three-headed dragon, and these three heads are guile, greed, and betrayal.
We encounter a similar metaphor in the concept of three unwholesome roots. Is it possible that choosing the word ‘khandha’ the Buddha had something like a banyan tree in His mind?
I think there may be something to it, even though I am not competent to make any authoritative judgement on the matter. Whoever is competent can consider it as an invitation to consider this hypothesis. Alternatively, the metaphor was not directly referring to the trunks but rather to the logs or log-like big chunks of timber, that would account for the upadana-fuel metaphor. In the banyan metaphor case, upadana is a bit more of a puzzle.
Connotations
I don’t think that many people apart from Ven. Sujato have any connotations in mind when hearing the word ‘aggregate’ apart from something along the lines of ‘boring, scholarly, what is that thing?’ 
Most of the time, the ‘aggregates’ do not appear in non-Dhamma contexts in our everyday life. This is why most newcomers to the Buddhism are fairly uncomfortable with it. They can even know what it means but the sheer irrelevance of the word for their previous experience makes it look as awkward and misplaced as a camel in Antarctica. People who are comfortable with the word are usually experienced Buddhists who learned to use the word by developing their own connotations and mental pictures. When they say they find ‘bundle’ no more informative, it can be because for them ‘aggregates’ have become more informative. If the Buddha wanted to use a word that doesn’t have any connotations connected with the everyday life, I think he could use more neutral terms like ‘sannipata’: this word closely corresponds with the Latin root words like ‘aggregate’ or ‘assemblage’ and, moreover, denotates something inherently composite.
Since we are discssing a possibilty, that compositeness was not inherent in the use of ‘khadhas’, ‘heaps’ and ‘bundles’ and other word having the element of compositeness in their denotation won’t do. Can we translate 'khandhas’as ‘trunks’? That is certainly more informative than ‘aggregates’ but I have lived my entire life in the regions of the world where there are no banyan trees, just as so many other speakers of English. For me, the word ‘trunk’ is still not very illustrative of the idea behind khandhas.
One could use the word ‘bodies’ but it would mess just two much with other doctrinal terms and besides has related words like ‘embodiment’, i.e. is a bit too avatar-like (in the Hindu sense of the word) for my taste. I like the word ‘heads’ better because Cerberus and three-headed beings quite frequently come up in the Western mythology and folk traditions and are more readily understandable for a Westerner. The major issue with ‘heads’ is that there aren’t any _five-_headed beings I know of.
An interesting variant, if consider the banyan metaphor, would be ‘fingers’. It is a bit problematic because it also evokes an image of a ‘hand’, and there is no hand (maybe ignorance or craving?) and it doesn’t rhyme well with upadana.
To conclude,
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What do you think about the multi-trunk metaphor?
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What do you think about the metaphorical opposition ‘solidness-compositeness’ that is reversed in the current translations of khandha?
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How would you satisfyingly translated ‘khandha’ into English within the banyan framework? It’s not necessary that you think this framework is correct, you can regard it as an exercise in translation: even I am agnostic about its status.
Upd.: This may be even more subjective, but to me the English words ‘bulk’, ‘mass’, ‘trunk’, ‘torso’ that are associated with ‘khandha’ have a slight connotation of something overbearing, looming large, that also kind of gets lost in translation. Still, as I said, it is highly subjective and may not be true for the Ancient Indic perception of these words.
So I vote for sticking with aggregate (albeit not great) unless an even better alternative works. When you see something as/call something a rock, it’s an aggreagate of ‘stuff’ glommed together, not a bundle of rocks. And isn’t bundle used already for another Pali word (kalāpa)? And while groups or subsets (or just sets) have essentially the same meaning as ‘bundle’ (and really a bit different than aggreagate), I would prefer these over ‘bundle’.
