Trial Pronouns

I'm not going to have pronouns in my language, but I got to thinking about them anyway.  Here they are in English:

	sing.	pl.
1st	I	we
2nd	you	*y'all
3rd anim.	he/she	them
3rd inanim.	it	them

Māori has singular and dual, for two of something.  Therefore, plural means 'three of more'.  Māori also distinguishes between 'we' that includes the hearer, and 'we' that excludes the hearer.  In English, we'd have to resort to "you and us", "y'all and us", "you and I", and "y'all and I".  Here's Māori:

	Sing.	Dual	Pl.
1st. excl.	Ahau, Au	Māua	Mātou
1st. incl.	-	Tāua	Tātou
2nd	Koe	Korua	Koutou
3rd	Ia	Rāua	Rātou

Na'vi has the singular, dual and trial numbers.  That means 'plural' means 'four or more'!  Here is the system of pronouns:

	Sing.	Dual	Trial	Plural
1st excl.	oe	moe	pxoe	ayoe
1st incl.	-	oeng	pxoeng	ayoeng, awnga
2nd	nga	menga	pxenga	aynga
3rd anim.	po	mefo	pxefo	ayfo, fo
3rd inanim.	tsa'u, tsaw	mesa'u	pxesa'u	aysa'u, sa'u

But one words seems weird: pxoeng.  It's the #3 prefix -- pxe+ -- plus the root 'I' -- oe -- plus most of the word for you -- ng.  Why doesn't that mean "the three of us and you'?  Don't get me wrong, I learned a lot from Na'vi, especially about the trial number.  I hadn't thought clearly about 1st person plural (or dual or trial) personal pronouns before, and the separation into 'exclusive' and 'inclusive' was enlightening.  Translating down the 'dual' column into English would read: "both of us, you and I, both of you, both of them, the two things."  But if we can split the English 'we' into two things in the dual, why can't we split the English 'we' into more things in the trial?  Let me illustrated with another table in *hypothetical Na'vi:

Word	Person A	Person B	Person C	English
pxoe	Me #1	Me #2	Me #3	"The three of us"
*moeng	Me #1	Me #2	You #1	"The two of us and you"
*oemenga	Me #1	You #1	You #2	"You two and I"
*moepo	Me #1	Me #2	Her #1	"The two of us and her"
*oemepo	Me #1	Her #1	Her #2	"Those two and I"
*oengpo	Me #1	You #1	Her #1	"You, me and her"
pxenga	You #1	You #2	You #3	"The three of you"
*mengapo	You #1	You #2	Her #1	"You two and her"
*ngamofo	You #1	Her #1	Her #2	"The two of them and you"
pxefo	Her #1	Her #2	Her #3	"The three of them"

Now I know this isn't as succinct, but couldn't you imagine that if a language was serious about the trial, it might do this?