MacArthur is not the issue, and he can be either ignored or dismissed. So let's focus on the actual issue. There is no contradiction between saying that Scripture is complete, and a multitude of prophecies remain unfulfilled. In the Holy Bible God has given to us all that we need (2 Tim 3:16,17). So here are some pertinent questions:
1. Is Scripture complete? Absolutely
2. Is the Bible perfect -- inspired, inerrant, and infallible? Absolutely
3. Did John say that no one should add any more prophecies to those in Revelation? Absolutely
4. Did Paul mean prophecies would cease? Paul said that they would cease (not fail even though it sounds like that in the KJV) and the word used in Greek is καταργηθήσονται (katargēthēsontai) derived from katargeo*.
*Strong's Concordance
katargeó: to render inoperative, abolish
Original Word: καταργέω
Part of Speech: Verb
Transliteration: katargeó
Phonetic Spelling: (kat-arg-eh'-o)
Definition: to render inoperative, abolish
Usage: (a) I make idle (inactive), make of no effect, annul, abolish, bring to naught, (b) I discharge, sever, separate from.
5. Did Paul tie prophecies, tongues, and supernatural knowledge together as a package of gifts that would cease? Absolutely
6. Did Paul say "that which is perfect/complete is come" or did he say "He who is perfect is come"? (meaning Christ). He did say the former, not the latter, and that was not careless or accidental.
7. Does the record show (Church Fathers and Church history) that for 1900 years those three gifts were not operational? Absolutely. Not a single Church Father claimed to be either (a) an apostle, or (b) a prophet, or (c) a tongues-speaker. But today claims are being made for all three.
So we need to go by a proper exegesis as well as a close examination of Church history to see that out of about 20 spiritual gifts these three have ceased. The classic work by Philip Schaff -- History of the Christian Church -- will confirm what I have said.
At the same time, Christians who are not Pentecostals or Charismatics do not have to interfere with, or deride, those who are. Each one is directly accountable to God. However there could be serious issues for the unwary if false tongues are being promoted (along with a lot of emotionalism and sometimes craziness) among certain groups. The description of the "Toronto Blessing" comes to mind.