Church Government was one of the main themes HWA taught. Even sending Gerald Waterhouse worldwide for many years to emphasize the importance of this doctrine. The importance is not just for now. It is a necessary lesson to learn for when we are powerful beings in the Kingdom of God. We won't be doing 'our thing'. We will be obedient to our husband Christ, through the chain of authority he establishes.
That is the lesson Laodiceans haven't yet learnt. That is probably why bringing back GTA to reconcile with his father to acknowledge his superior God-given authority for all the Church to see, is important.
All Philadelphia and repentant Laodiceans resurrected immortal are likely to be working under HWA who trained them, in the Millennium.
Imagine the impact on the Church if they saw a resurrected HWA measuring the groups there are now.
Imagine the hope for sinners if a resurrected GTA repented and did powerful things because of it.
The world remembers them. Their return would stop the world in its tracks and make everyone sit up and take notice, especially the church which has for the most part discarded the teachings of Herbert Armstrong and devalued his position.
He would be uniquely qualified to 'measure' as Zerubbabel is told to do.
All of this revolves around HWA being resurrected first. Then GTA will be resurrected so he can reconcile with HWA. Then the two will join forces and restore the Church of God to it's rightful state in the universe and then become the Two Witnesses.
Most of the world does not remember them, they have no idea who they even were! They have made no impact and most assuredly the hundreds of splinter groups today are not making any impact either!