My suggestions below. (Please stick with it until the end, so you can see where I'm coming from) :
Replace the current GCSE with a 5 paper exam, to include:
a) Listening: all questions in English, requiring answers in English. No dictionary needed as there is no written French to look up.
b) Reading: all questions in English, requiring answers in English. Dictionary allowed. Reading could include an element of translation from the TL into English!
c) Language in Use / Grammar: similar to the papers used in the Cambridge EFL exams. Tests of grammar and vocabulary in context. Manipulation of language and structures. No dictionary.
d) Speaking: assessment by external examiner. No indication beforehand of content. Mix of transactional language, conversation and e.g. describing / discussing a picture. Emphasis on assessing the students' ability to produce spontaneous appropriate utterances in response to aural or visual stimuli.
e) Writing: by final exam. Dictionary allowed (but use discouraged). Variety of question types and stimuli. e.g. maybe include something like the old-style picture essay. Include lower level questions, and all questions / instructions to be in English. Include some translation into the target language (or something similar based on getting a particular message across in their own words).
(All of the above equally weighted: 20% each)
Maybe combine L + R into one "receptive skills" exam, divided into 2 parts.
Or
put Reading & Writing together as one paper, and then Listening
& Language in Use together on a different day, as neither of these
require dictionaries. (So essentially 2 sessions - a dictionary session
and a no dictionary session.)
Now, this may appear old-fashioned, rather than forward-thinking, BUT...
An exam structure like the one above would make a teaching style based on memorising whole chunks of text or set responses to pre-prepared questions obsolete and unworkable. (There would simply be no point in doing this...) The only way to get students to pass exams would be to teach them how to actually use language themselves.
Then the interesting bit (and the forward-thinking bit) would be to experiment with all kinds of techniques which would allow students to become effective learners, users and manipulators of language.